From 0c84f4017f576bd250e4408d8410f6647507027c Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Tue, 21 Jan 2020 14:26:15 +0100
Subject: [PATCH 01/37] 3.x: Fix method argument naming across types (#6853)

* 3.x: Fix method argument naming across types

* Remove outdated null-test of blockingMostRecent
---
 .../reactivex/rxjava3/core/Completable.java   | 152 +++++-----
 .../io/reactivex/rxjava3/core/Flowable.java   | 148 +++++-----
 .../java/io/reactivex/rxjava3/core/Maybe.java | 111 ++++----
 .../io/reactivex/rxjava3/core/Observable.java | 269 +++++++++---------
 .../io/reactivex/rxjava3/core/Single.java     | 154 +++++-----
 .../BlockingFlowableMostRecentTest.java       |   4 -
 .../BlockingObservableMostRecentTest.java     |   4 -
 .../internal/util/OperatorArgumentNaming.java | 169 +++++++++++
 .../ParamValidationCheckerTest.java           |   6 -
 .../validators/ParamValidationNaming.java     |   2 +-
 10 files changed, 591 insertions(+), 428 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/util/OperatorArgumentNaming.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index ee3af955a9..1266255315 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -332,21 +332,21 @@ public static Completable create(@NonNull CompletableOnSubscribe source) {
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code unsafeCreate} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param source the callback which will receive the {@link CompletableObserver} instances
+     * @param onSubscribe the callback which will receive the {@link CompletableObserver} instances
      * when the {@code Completable} is subscribed to.
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code source} is {@code null}
+     * @throws NullPointerException if {@code onSubscribe} is {@code null}
      * @throws IllegalArgumentException if {@code source} is a {@code Completable}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static Completable unsafeCreate(@NonNull CompletableSource source) {
-        Objects.requireNonNull(source, "source is null");
-        if (source instanceof Completable) {
+    public static Completable unsafeCreate(@NonNull CompletableSource onSubscribe) {
+        Objects.requireNonNull(onSubscribe, "onSubscribe is null");
+        if (onSubscribe instanceof Completable) {
             throw new IllegalArgumentException("Use of unsafeCreate(Completable)!");
         }
-        return RxJavaPlugins.onAssembly(new CompletableFromUnsafeSource(source));
+        return RxJavaPlugins.onAssembly(new CompletableFromUnsafeSource(onSubscribe));
     }
 
     /**
@@ -357,16 +357,16 @@ public static Completable unsafeCreate(@NonNull CompletableSource source) {
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code defer} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param completableSupplier the supplier that returns the {@code Completable} that will be subscribed to.
+     * @param supplier the supplier that returns the {@code Completable} that will be subscribed to.
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code completableSupplier} is {@code null}
+     * @throws NullPointerException if {@code supplier} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static Completable defer(@NonNull Supplier<? extends CompletableSource> completableSupplier) {
-        Objects.requireNonNull(completableSupplier, "completableSupplier is null");
-        return RxJavaPlugins.onAssembly(new CompletableDefer(completableSupplier));
+    public static Completable defer(@NonNull Supplier<? extends CompletableSource> supplier) {
+        Objects.requireNonNull(supplier, "supplier is null");
+        return RxJavaPlugins.onAssembly(new CompletableDefer(supplier));
     }
 
     /**
@@ -381,16 +381,16 @@ public static Completable defer(@NonNull Supplier<? extends CompletableSource> c
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param errorSupplier the error supplier, not {@code null}
+     * @param supplier the error supplier, not {@code null}
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code errorSupplier} is {@code null}
+     * @throws NullPointerException if {@code supplier} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static Completable error(@NonNull Supplier<? extends Throwable> errorSupplier) {
-        Objects.requireNonNull(errorSupplier, "errorSupplier is null");
-        return RxJavaPlugins.onAssembly(new CompletableErrorSupplier(errorSupplier));
+    public static Completable error(@NonNull Supplier<? extends Throwable> supplier) {
+        Objects.requireNonNull(supplier, "supplier is null");
+        return RxJavaPlugins.onAssembly(new CompletableErrorSupplier(supplier));
     }
 
     /**
@@ -401,16 +401,16 @@ public static Completable error(@NonNull Supplier<? extends Throwable> errorSupp
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param error the {@code Throwable} instance to emit, not {@code null}
+     * @param throwable the {@code Throwable} instance to emit, not {@code null}
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code error} is {@code null}
+     * @throws NullPointerException if {@code throwable} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static Completable error(@NonNull Throwable error) {
-        Objects.requireNonNull(error, "error is null");
-        return RxJavaPlugins.onAssembly(new CompletableError(error));
+    public static Completable error(@NonNull Throwable throwable) {
+        Objects.requireNonNull(throwable, "throwable is null");
+        return RxJavaPlugins.onAssembly(new CompletableError(throwable));
     }
 
     /**
@@ -429,16 +429,16 @@ public static Completable error(@NonNull Throwable error) {
      *  {@link RxJavaPlugins#onError(Throwable)} as an {@link io.reactivex.rxjava3.exceptions.UndeliverableException UndeliverableException}.
      *  </dd>
      * </dl>
-     * @param run the {@code Action} to run for each subscribing {@link CompletableObserver}
+     * @param action the {@code Action} to run for each subscribing {@link CompletableObserver}
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code run} is {@code null}
+     * @throws NullPointerException if {@code action} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static Completable fromAction(@NonNull Action run) {
-        Objects.requireNonNull(run, "run is null");
-        return RxJavaPlugins.onAssembly(new CompletableFromAction(run));
+    public static Completable fromAction(@NonNull Action action) {
+        Objects.requireNonNull(action, "action is null");
+        return RxJavaPlugins.onAssembly(new CompletableFromAction(action));
     }
 
     /**
@@ -1029,19 +1029,19 @@ private static NullPointerException toNpe(Throwable ex) {
      * </dl>
      * @param <R> the resource type
      * @param resourceSupplier the {@link Supplier} that returns a resource to be managed.
-     * @param completableFunction the {@link Function} that given a resource returns a {@code CompletableSource} instance that will be subscribed to
-     * @param disposer the {@link Consumer} that disposes the resource created by the resource supplier
+     * @param sourceSupplier the {@link Function} that given a resource returns a {@code CompletableSource} instance that will be subscribed to
+     * @param resourceCleanup the {@link Consumer} that disposes the resource created by the resource supplier
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code completableFunction}
-     *                              or {@code disposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier}
+     *                              or {@code resourceCleanup} is {@code null}
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public static <R> Completable using(@NonNull Supplier<R> resourceSupplier,
-            @NonNull Function<? super R, ? extends CompletableSource> completableFunction,
-            @NonNull Consumer<? super R> disposer) {
-        return using(resourceSupplier, completableFunction, disposer, true);
+            @NonNull Function<? super R, ? extends CompletableSource> sourceSupplier,
+            @NonNull Consumer<? super R> resourceCleanup) {
+        return using(resourceSupplier, sourceSupplier, resourceCleanup, true);
     }
 
     /**
@@ -1059,31 +1059,31 @@ public static <R> Completable using(@NonNull Supplier<R> resourceSupplier,
      * </dl>
      * @param <R> the resource type
      * @param resourceSupplier the {@link Supplier} that returns a resource to be managed
-     * @param completableFunction the {@link Function} that given a resource returns a non-{@code null}
+     * @param sourceSupplier the {@link Function} that given a resource returns a non-{@code null}
      * {@code CompletableSource} instance that will be subscribed to
-     * @param disposer the {@link Consumer} that disposes the resource created by the resource supplier
+     * @param resourceCleanup the {@link Consumer} that disposes the resource created by the resource supplier
      * @param eager
      *            If {@code true} then resource disposal will happen either on a {@code dispose()} call before the upstream is disposed
      *            or just before the emission of a terminal event ({@code onComplete} or {@code onError}).
      *            If {@code false} the resource disposal will happen either on a {@code dispose()} call after the upstream is disposed
      *            or just after the emission of a terminal event ({@code onComplete} or {@code onError}).
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code completableFunction}
-     *                              or {@code disposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier}
+     *                              or {@code resourceCleanup} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <R> Completable using(
             @NonNull Supplier<R> resourceSupplier,
-            @NonNull Function<? super R, ? extends CompletableSource> completableFunction,
-            @NonNull Consumer<? super R> disposer,
+            @NonNull Function<? super R, ? extends CompletableSource> sourceSupplier,
+            @NonNull Consumer<? super R> resourceCleanup,
             boolean eager) {
         Objects.requireNonNull(resourceSupplier, "resourceSupplier is null");
-        Objects.requireNonNull(completableFunction, "completableFunction is null");
-        Objects.requireNonNull(disposer, "disposer is null");
+        Objects.requireNonNull(sourceSupplier, "sourceSupplier is null");
+        Objects.requireNonNull(resourceCleanup, "resourceCleanup is null");
 
-        return RxJavaPlugins.onAssembly(new CompletableUsing<>(resourceSupplier, completableFunction, disposer, eager));
+        return RxJavaPlugins.onAssembly(new CompletableUsing<>(resourceSupplier, sourceSupplier, resourceCleanup, eager));
     }
 
     /**
@@ -1390,7 +1390,7 @@ public final Completable concatWith(@NonNull CompletableSource other) {
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code delay} does operate by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
-     * @param delay the delay time
+     * @param time the delay time
      * @param unit the delay unit
      * @return the new {@code Completable} instance
      * @throws NullPointerException if {@code unit} is {@code null}
@@ -1398,8 +1398,8 @@ public final Completable concatWith(@NonNull CompletableSource other) {
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Completable delay(long delay, @NonNull TimeUnit unit) {
-        return delay(delay, unit, Schedulers.computation(), false);
+    public final Completable delay(long time, @NonNull TimeUnit unit) {
+        return delay(time, unit, Schedulers.computation(), false);
     }
 
     /**
@@ -1411,7 +1411,7 @@ public final Completable delay(long delay, @NonNull TimeUnit unit) {
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code delay} operates on the {@code Scheduler} you specify.</dd>
      * </dl>
-     * @param delay the delay time
+     * @param time the delay time
      * @param unit the delay unit
      * @param scheduler the {@code Scheduler} to run the delayed completion on
      * @return the new {@code Completable} instance
@@ -1420,8 +1420,8 @@ public final Completable delay(long delay, @NonNull TimeUnit unit) {
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Completable delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return delay(delay, unit, scheduler, false);
+    public final Completable delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delay(time, unit, scheduler, false);
     }
 
     /**
@@ -1433,7 +1433,7 @@ public final Completable delay(long delay, @NonNull TimeUnit unit, @NonNull Sche
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code delay} operates on the {@code Scheduler} you specify.</dd>
      * </dl>
-     * @param delay the delay time
+     * @param time the delay time
      * @param unit the delay unit
      * @param scheduler the {@code Scheduler} to run the delayed completion on
      * @param delayError delay the error emission as well?
@@ -1443,10 +1443,10 @@ public final Completable delay(long delay, @NonNull TimeUnit unit, @NonNull Sche
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    public final Completable delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
+    public final Completable delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
-        return RxJavaPlugins.onAssembly(new CompletableDelay(this, delay, unit, scheduler, delayError));
+        return RxJavaPlugins.onAssembly(new CompletableDelay(this, time, unit, scheduler, delayError));
     }
 
     /**
@@ -1459,7 +1459,7 @@ public final Completable delay(long delay, @NonNull TimeUnit unit, @NonNull Sche
      * </dl>
      * <p>History: 2.2.3 - experimental
      *
-     * @param delay the time to delay the subscription
+     * @param time the time to delay the subscription
      * @param unit  the time unit of {@code delay}
      * @return the new {@code Completable} instance
      * @throws NullPointerException if {@code unit} is {@code null}
@@ -1469,8 +1469,8 @@ public final Completable delay(long delay, @NonNull TimeUnit unit, @NonNull Sche
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Completable delaySubscription(long delay, @NonNull TimeUnit unit) {
-        return delaySubscription(delay, unit, Schedulers.computation());
+    public final Completable delaySubscription(long time, @NonNull TimeUnit unit) {
+        return delaySubscription(time, unit, Schedulers.computation());
     }
 
     /**
@@ -1483,7 +1483,7 @@ public final Completable delaySubscription(long delay, @NonNull TimeUnit unit) {
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
      * </dl>
      * <p>History: 2.2.3 - experimental
-     * @param delay     the time to delay the subscription
+     * @param time     the time to delay the subscription
      * @param unit      the time unit of {@code delay}
      * @param scheduler the {@code Scheduler} on which the waiting and subscription will happen
      * @return the new {@code Completable} instance
@@ -1494,8 +1494,8 @@ public final Completable delaySubscription(long delay, @NonNull TimeUnit unit) {
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Completable delaySubscription(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return Completable.timer(delay, unit, scheduler).andThen(this);
+    public final Completable delaySubscription(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return Completable.timer(time, unit, scheduler).andThen(this);
     }
 
     /**
@@ -1974,17 +1974,17 @@ public final Completable onErrorComplete(@NonNull Predicate<? super Throwable> p
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param errorMapper the {@code mapper} {@code Function} that takes the error and should return a {@code CompletableSource} as
+     * @param fallbackSupplier the {@code mapper} {@code Function} that takes the error and should return a {@code CompletableSource} as
      * continuation.
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code errorMapper} is {@code null}
+     * @throws NullPointerException if {@code fallbackSupplier} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Completable onErrorResumeNext(@NonNull Function<? super Throwable, ? extends CompletableSource> errorMapper) {
-        Objects.requireNonNull(errorMapper, "errorMapper is null");
-        return RxJavaPlugins.onAssembly(new CompletableResumeNext(this, errorMapper));
+    public final Completable onErrorResumeNext(@NonNull Function<? super Throwable, ? extends CompletableSource> fallbackSupplier) {
+        Objects.requireNonNull(fallbackSupplier, "fallbackSupplier is null");
+        return RxJavaPlugins.onAssembly(new CompletableResumeNext(this, fallbackSupplier));
     }
 
     /**
@@ -2544,16 +2544,16 @@ public final Completable timeout(long timeout, @NonNull TimeUnit unit) {
      * </dl>
      * @param timeout the timeout value
      * @param unit the unit of {@code timeout}
-     * @param other the other {@code CompletableSource} instance to switch to in case of a timeout
+     * @param fallback the other {@code CompletableSource} instance to switch to in case of a timeout
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code unit} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit} or {@code fallback} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
-    public final Completable timeout(long timeout, @NonNull TimeUnit unit, @NonNull CompletableSource other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(timeout, unit, Schedulers.computation(), other);
+    public final Completable timeout(long timeout, @NonNull TimeUnit unit, @NonNull CompletableSource fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(timeout, unit, Schedulers.computation(), fallback);
     }
 
     /**
@@ -2593,16 +2593,16 @@ public final Completable timeout(long timeout, @NonNull TimeUnit unit, @NonNull
      * @param timeout the timeout value
      * @param unit the unit of {@code timeout}
      * @param scheduler the {@code Scheduler} to use to wait for completion
-     * @param other the other {@code Completable} instance to switch to in case of a timeout
+     * @param fallback the other {@code Completable} instance to switch to in case of a timeout
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code fallback} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    public final Completable timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull CompletableSource other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(timeout, unit, scheduler, other);
+    public final Completable timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull CompletableSource fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(timeout, unit, scheduler, fallback);
     }
 
     /**
@@ -2616,18 +2616,18 @@ public final Completable timeout(long timeout, @NonNull TimeUnit unit, @NonNull
      * @param timeout the timeout value
      * @param unit the unit of {@code timeout}
      * @param scheduler the {@code Scheduler} to use to wait for completion
-     * @param other the other {@code Completable} instance to switch to in case of a timeout,
+     * @param fallback the other {@code Completable} instance to switch to in case of a timeout,
      * if {@code null} a {@link TimeoutException} is emitted instead
      * @return the new {@code Completable} instance
-     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code fallback} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    private Completable timeout0(long timeout, TimeUnit unit, Scheduler scheduler, CompletableSource other) {
+    private Completable timeout0(long timeout, TimeUnit unit, Scheduler scheduler, CompletableSource fallback) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
-        return RxJavaPlugins.onAssembly(new CompletableTimeout(this, timeout, unit, scheduler, other));
+        return RxJavaPlugins.onAssembly(new CompletableTimeout(this, timeout, unit, scheduler, fallback));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 54bc24fca0..038c3f680b 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -2178,9 +2178,9 @@ public static <T> Flowable<T> error(@NonNull Throwable throwable) {
      *  <dd>{@code fromPublisher} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the value type of the flow
-     * @param source the {@code Publisher} to convert
+     * @param publisher the {@code Publisher} to convert
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if the {@code source} {@code Publisher} is {@code null}
+     * @throws NullPointerException if {@code publisher} is {@code null}
      * @see #create(FlowableOnSubscribe, BackpressureStrategy)
      */
     @CheckReturnValue
@@ -2188,13 +2188,13 @@ public static <T> Flowable<T> error(@NonNull Throwable throwable) {
     @BackpressureSupport(BackpressureKind.PASS_THROUGH)
     @SchedulerSupport(SchedulerSupport.NONE)
     @SuppressWarnings("unchecked")
-    public static <T> Flowable<T> fromPublisher(@NonNull Publisher<@NonNull ? extends T> source) {
-        if (source instanceof Flowable) {
-            return RxJavaPlugins.onAssembly((Flowable<T>)source);
+    public static <T> Flowable<T> fromPublisher(@NonNull Publisher<@NonNull ? extends T> publisher) {
+        if (publisher instanceof Flowable) {
+            return RxJavaPlugins.onAssembly((Flowable<T>)publisher);
         }
-        Objects.requireNonNull(source, "source is null");
+        Objects.requireNonNull(publisher, "publisher is null");
 
-        return RxJavaPlugins.onAssembly(new FlowableFromPublisher<>(source));
+        return RxJavaPlugins.onAssembly(new FlowableFromPublisher<>(publisher));
     }
 
     /**
@@ -4514,10 +4514,10 @@ public static <T> Flowable<T> unsafeCreate(@NonNull Publisher<T> onSubscribe) {
      *            the factory function to create a resource object that depends on the {@code Publisher}
      * @param sourceSupplier
      *            the factory function to create a {@code Publisher}
-     * @param resourceDisposer
+     * @param resourceCleanup
      *            the function that will dispose of the resource
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceDisposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceCleanup} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
      */
     @CheckReturnValue
@@ -4527,8 +4527,8 @@ public static <T> Flowable<T> unsafeCreate(@NonNull Publisher<T> onSubscribe) {
     public static <T, D> Flowable<T> using(
             @NonNull Supplier<? extends D> resourceSupplier,
             @NonNull Function<? super D, ? extends Publisher<@NonNull ? extends T>> sourceSupplier,
-            @NonNull Consumer<? super D> resourceDisposer) {
-        return using(resourceSupplier, sourceSupplier, resourceDisposer, true);
+            @NonNull Consumer<? super D> resourceCleanup) {
+        return using(resourceSupplier, sourceSupplier, resourceCleanup, true);
     }
 
     /**
@@ -4551,7 +4551,7 @@ public static <T, D> Flowable<T> using(
      *            the factory function to create a resource object that depends on the {@code Publisher}
      * @param sourceSupplier
      *            the factory function to create a {@code Publisher}
-     * @param resourceDisposer
+     * @param resourceCleanup
      *            the function that will dispose of the resource
      * @param eager
      *            If {@code true}, the resource disposal will happen either on a {@code cancel()} call before the upstream is disposed
@@ -4559,7 +4559,7 @@ public static <T, D> Flowable<T> using(
      *            If {@code false} the resource disposal will happen either on a {@code cancel()} call after the upstream is disposed
      *            or just after the emission of a terminal event ({@code onComplete} or {@code onError}).
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceDisposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceCleanup} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
      * @since 2.0
      */
@@ -4570,12 +4570,12 @@ public static <T, D> Flowable<T> using(
     public static <T, D> Flowable<T> using(
             @NonNull Supplier<? extends D> resourceSupplier,
             @NonNull Function<? super D, ? extends Publisher<@NonNull ? extends T>> sourceSupplier,
-            @NonNull Consumer<? super D> resourceDisposer,
+            @NonNull Consumer<? super D> resourceCleanup,
             boolean eager) {
         Objects.requireNonNull(resourceSupplier, "resourceSupplier is null");
         Objects.requireNonNull(sourceSupplier, "sourceSupplier is null");
-        Objects.requireNonNull(resourceDisposer, "resourceDisposer is null");
-        return RxJavaPlugins.onAssembly(new FlowableUsing<T, D>(resourceSupplier, sourceSupplier, resourceDisposer, eager));
+        Objects.requireNonNull(resourceCleanup, "resourceCleanup is null");
+        return RxJavaPlugins.onAssembly(new FlowableUsing<T, D>(resourceSupplier, sourceSupplier, resourceCleanup, eager));
     }
 
     /**
@@ -5944,6 +5944,7 @@ public final Iterable<T> blockingLatest() {
      *            the initial item that the {@code Iterable} sequence will yield if this
      *            {@code Flowable} has not yet emitted an item
      * @return the new {@code Iterable} instance
+     * @throws NullPointerException if {@code initialItem} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/first.html">ReactiveX documentation: First</a>
      */
     @CheckReturnValue
@@ -5951,6 +5952,7 @@ public final Iterable<T> blockingLatest() {
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public final Iterable<T> blockingMostRecent(@NonNull T initialItem) {
+        Objects.requireNonNull(initialItem, "initialItem is null");
         return new BlockingFlowableMostRecent<>(this, initialItem);
     }
 
@@ -8616,7 +8618,7 @@ public final <U> Flowable<T> delay(@NonNull Function<? super T, ? extends Publis
      *  <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the {@link TimeUnit} in which {@code period} is defined
@@ -8628,8 +8630,8 @@ public final <U> Flowable<T> delay(@NonNull Function<? super T, ? extends Publis
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Flowable<T> delay(long delay, @NonNull TimeUnit unit) {
-        return delay(delay, unit, Schedulers.computation(), false);
+    public final Flowable<T> delay(long time, @NonNull TimeUnit unit) {
+        return delay(time, unit, Schedulers.computation(), false);
     }
 
     /**
@@ -8644,7 +8646,7 @@ public final Flowable<T> delay(long delay, @NonNull TimeUnit unit) {
      *  <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the {@link TimeUnit} in which {@code period} is defined
@@ -8659,8 +8661,8 @@ public final Flowable<T> delay(long delay, @NonNull TimeUnit unit) {
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, boolean delayError) {
-        return delay(delay, unit, Schedulers.computation(), delayError);
+    public final Flowable<T> delay(long time, @NonNull TimeUnit unit, boolean delayError) {
+        return delay(time, unit, Schedulers.computation(), delayError);
     }
 
     /**
@@ -8675,7 +8677,7 @@ public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, boolean delay
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the time unit of {@code delay}
@@ -8689,8 +8691,8 @@ public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, boolean delay
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return delay(delay, unit, scheduler, false);
+    public final Flowable<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delay(time, unit, scheduler, false);
     }
 
     /**
@@ -8705,7 +8707,7 @@ public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Sche
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the time unit of {@code delay}
@@ -8722,11 +8724,11 @@ public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Sche
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    public final Flowable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
+    public final Flowable<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
 
-        return RxJavaPlugins.onAssembly(new FlowableDelay<>(this, Math.max(0L, delay), unit, scheduler, delayError));
+        return RxJavaPlugins.onAssembly(new FlowableDelay<>(this, Math.max(0L, time), unit, scheduler, delayError));
     }
 
     /**
@@ -8807,7 +8809,7 @@ public final <U> Flowable<T> delaySubscription(@NonNull Publisher<U> subscriptio
      *  <dd>This version of {@code delaySubscription} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the time to delay the subscription
      * @param unit
      *            the time unit of {@code delay}
@@ -8819,8 +8821,8 @@ public final <U> Flowable<T> delaySubscription(@NonNull Publisher<U> subscriptio
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Flowable<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
-        return delaySubscription(delay, unit, Schedulers.computation());
+    public final Flowable<T> delaySubscription(long time, @NonNull TimeUnit unit) {
+        return delaySubscription(time, unit, Schedulers.computation());
     }
 
     /**
@@ -8835,7 +8837,7 @@ public final Flowable<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the time to delay the subscription
      * @param unit
      *            the time unit of {@code delay}
@@ -8849,8 +8851,8 @@ public final Flowable<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Flowable<T> delaySubscription(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return delaySubscription(timer(delay, unit, scheduler));
+    public final Flowable<T> delaySubscription(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delaySubscription(timer(time, unit, scheduler));
     }
 
     /**
@@ -12334,20 +12336,20 @@ public final Flowable<T> onBackpressureLatest() {
      *  <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param resumeFunction
+     * @param fallbackSupplier
      *            a function that returns a {@code Publisher} that will take over if the current {@code Flowable} encounters
      *            an error
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code resumeFunction} is {@code null}
+     * @throws NullPointerException if {@code fallbackSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Flowable<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? extends Publisher<@NonNull ? extends T>> resumeFunction) {
-        Objects.requireNonNull(resumeFunction, "resumeFunction is null");
-        return RxJavaPlugins.onAssembly(new FlowableOnErrorNext<>(this, resumeFunction));
+    public final Flowable<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? extends Publisher<@NonNull ? extends T>> fallbackSupplier) {
+        Objects.requireNonNull(fallbackSupplier, "fallbackSupplier is null");
+        return RxJavaPlugins.onAssembly(new FlowableOnErrorNext<>(this, fallbackSupplier));
     }
 
     /**
@@ -12379,20 +12381,20 @@ public final Flowable<T> onErrorResumeNext(@NonNull Function<? super Throwable,
      *  <dd>{@code onErrorResumeWith} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param next
+     * @param fallback
      *            the next {@code Publisher} source that will take over if the current {@code Flowable} encounters
      *            an error
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code next} is {@code null}
+     * @throws NullPointerException if {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Flowable<T> onErrorResumeWith(@NonNull Publisher<@NonNull ? extends T> next) {
-        Objects.requireNonNull(next, "next is null");
-        return onErrorResumeNext(Functions.justFunction(next));
+    public final Flowable<T> onErrorResumeWith(@NonNull Publisher<@NonNull ? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return onErrorResumeNext(Functions.justFunction(fallback));
     }
 
     /**
@@ -12420,20 +12422,20 @@ public final Flowable<T> onErrorResumeWith(@NonNull Publisher<@NonNull ? extends
      *  <dd>{@code onErrorReturn} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param valueSupplier
+     * @param itemSupplier
      *            a function that returns a single value that will be emitted along with a regular {@code onComplete} in case
      *            the current {@code Flowable} signals an {@code onError} event
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code valueSupplier} is {@code null}
+     * @throws NullPointerException if {@code itemSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Flowable<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> valueSupplier) {
-        Objects.requireNonNull(valueSupplier, "valueSupplier is null");
-        return RxJavaPlugins.onAssembly(new FlowableOnErrorReturn<>(this, valueSupplier));
+    public final Flowable<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> itemSupplier) {
+        Objects.requireNonNull(itemSupplier, "itemSupplier is null");
+        return RxJavaPlugins.onAssembly(new FlowableOnErrorReturn<>(this, itemSupplier));
     }
 
     /**
@@ -16918,19 +16920,19 @@ public final <V> Flowable<T> timeout(@NonNull Function<? super T, ? extends Publ
      * @param itemTimeoutIndicator
      *            a function that returns a {@code Publisher}, for each item emitted by the current {@code Flowable}, that
      *            determines the timeout window for the subsequent item
-     * @param other
+     * @param fallback
      *            the fallback {@code Publisher} to switch to if the current {@code Flowable} times out
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code itemTimeoutIndicator} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code itemTimeoutIndicator} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final <V> Flowable<T> timeout(@NonNull Function<? super T, ? extends Publisher<@NonNull V>> itemTimeoutIndicator, @NonNull Publisher<@NonNull ? extends T> other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(null, itemTimeoutIndicator, other);
+    public final <V> Flowable<T> timeout(@NonNull Function<? super T, ? extends Publisher<@NonNull V>> itemTimeoutIndicator, @NonNull Publisher<@NonNull ? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(null, itemTimeoutIndicator, fallback);
     }
 
     /**
@@ -16983,19 +16985,19 @@ public final Flowable<T> timeout(long timeout, @NonNull TimeUnit unit) {
      *            maximum duration between items before a timeout occurs
      * @param unit
      *            the unit of time that applies to the {@code timeout} argument
-     * @param other
+     * @param fallback
      *            the fallback {@code Publisher} to use in case of a timeout
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code unit} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
-    public final Flowable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Publisher<@NonNull ? extends T> other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(timeout, unit, other, Schedulers.computation());
+    public final Flowable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Publisher<@NonNull ? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(timeout, unit, fallback, Schedulers.computation());
     }
 
     /**
@@ -17021,19 +17023,19 @@ public final Flowable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull
      *            the unit of time that applies to the {@code timeout} argument
      * @param scheduler
      *            the {@code Scheduler} to run the timeout timers on
-     * @param other
+     * @param fallback
      *            the {@code Publisher} to use as the fallback in case of a timeout
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    public final Flowable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull Publisher<@NonNull ? extends T> other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(timeout, unit, other, scheduler);
+    public final Flowable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull Publisher<@NonNull ? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(timeout, unit, fallback, scheduler);
     }
 
     /**
@@ -17136,10 +17138,10 @@ public final <U, V> Flowable<T> timeout(@NonNull Publisher<U> firstTimeoutIndica
      *            a function that returns a {@code Publisher} for each item emitted by the current {@code Flowable} and that
      *            determines the timeout window in which the subsequent source item must arrive in order to
      *            continue the sequence
-     * @param other
+     * @param fallback
      *            the fallback {@code Publisher} to switch to if the current {@code Flowable} times out
      * @return the new {@code Flowable} instance
-     * @throws NullPointerException if {@code firstTimeoutIndicator}, {@code itemTimeoutIndicator} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code firstTimeoutIndicator}, {@code itemTimeoutIndicator} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
@@ -17149,25 +17151,25 @@ public final <U, V> Flowable<T> timeout(@NonNull Publisher<U> firstTimeoutIndica
     public final <U, V> Flowable<T> timeout(
             @NonNull Publisher<U> firstTimeoutIndicator,
             @NonNull Function<? super T, ? extends Publisher<V>> itemTimeoutIndicator,
-            @NonNull Publisher<@NonNull ? extends T> other) {
+            @NonNull Publisher<@NonNull ? extends T> fallback) {
         Objects.requireNonNull(firstTimeoutIndicator, "firstTimeoutIndicator is null");
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(firstTimeoutIndicator, itemTimeoutIndicator, other);
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(firstTimeoutIndicator, itemTimeoutIndicator, fallback);
     }
 
-    private Flowable<T> timeout0(long timeout, TimeUnit unit, Publisher<@NonNull ? extends T> other,
+    private Flowable<T> timeout0(long timeout, TimeUnit unit, Publisher<@NonNull ? extends T> fallback,
             Scheduler scheduler) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
-        return RxJavaPlugins.onAssembly(new FlowableTimeoutTimed<>(this, timeout, unit, scheduler, other));
+        return RxJavaPlugins.onAssembly(new FlowableTimeoutTimed<>(this, timeout, unit, scheduler, fallback));
     }
 
     private <U, V> Flowable<T> timeout0(
             Publisher<U> firstTimeoutIndicator,
             Function<? super T, ? extends Publisher<@NonNull V>> itemTimeoutIndicator,
-                    Publisher<@NonNull ? extends T> other) {
+                    Publisher<@NonNull ? extends T> fallback) {
         Objects.requireNonNull(itemTimeoutIndicator, "itemTimeoutIndicator is null");
-        return RxJavaPlugins.onAssembly(new FlowableTimeout<>(this, firstTimeoutIndicator, itemTimeoutIndicator, other));
+        return RxJavaPlugins.onAssembly(new FlowableTimeout<>(this, firstTimeoutIndicator, itemTimeoutIndicator, fallback));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 82cb7545c2..4322afaa93 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -620,17 +620,17 @@ public static <T> Maybe<T> create(@NonNull MaybeOnSubscribe<T> onSubscribe) {
      * <dd>{@code defer} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the value type
-     * @param maybeSupplier the {@code Supplier} that is called for each individual {@code MaybeObserver} and
+     * @param supplier the {@code Supplier} that is called for each individual {@code MaybeObserver} and
      * returns a {@code MaybeSource} instance to subscribe to
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code maybeSupplier} is {@code null}
+     * @throws NullPointerException if {@code supplier} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Maybe<T> defer(@NonNull Supplier<? extends MaybeSource<? extends T>> maybeSupplier) {
-        Objects.requireNonNull(maybeSupplier, "maybeSupplier is null");
-        return RxJavaPlugins.onAssembly(new MaybeDefer<>(maybeSupplier));
+    public static <T> Maybe<T> defer(@NonNull Supplier<? extends MaybeSource<? extends T>> supplier) {
+        Objects.requireNonNull(supplier, "supplier is null");
+        return RxJavaPlugins.onAssembly(new MaybeDefer<>(supplier));
     }
 
     /**
@@ -663,20 +663,20 @@ public static <T> Maybe<T> empty() {
      * <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param error
+     * @param throwable
      *            the particular {@link Throwable} to pass to {@link MaybeObserver#onError onError}
      * @param <T>
      *            the type of the item (ostensibly) emitted by the {@code Maybe}
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code error} is {@code null}
+     * @throws NullPointerException if {@code throwable} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Maybe<T> error(@NonNull Throwable error) {
-        Objects.requireNonNull(error, "error is null");
-        return RxJavaPlugins.onAssembly(new MaybeError<>(error));
+    public static <T> Maybe<T> error(@NonNull Throwable throwable) {
+        Objects.requireNonNull(throwable, "throwable is null");
+        return RxJavaPlugins.onAssembly(new MaybeError<>(throwable));
     }
 
     /**
@@ -760,16 +760,16 @@ public static <T> Maybe<T> fromCompletable(@NonNull CompletableSource completabl
      *  <dd>{@code fromSingle} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the target type
-     * @param singleSource the {@code SingleSource} to convert from
+     * @param single the {@code SingleSource} to convert from
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code singleSource} is {@code null}
+     * @throws NullPointerException if {@code single} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> singleSource) {
-        Objects.requireNonNull(singleSource, "singleSource is null");
-        return RxJavaPlugins.onAssembly(new MaybeFromSingle<>(singleSource));
+    public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
+        Objects.requireNonNull(single, "single is null");
+        return RxJavaPlugins.onAssembly(new MaybeFromSingle<>(single));
     }
 
     /**
@@ -1799,9 +1799,10 @@ public static <T> Maybe<T> unsafeCreate(@NonNull MaybeSource<T> onSubscribe) {
      *            the factory function to create a resource object that depends on the {@code Maybe}
      * @param sourceSupplier
      *            the factory function to create a {@code MaybeSource}
-     * @param resourceDisposer
+     * @param resourceCleanup
      *            the function that will dispose of the resource
      * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceCleanup} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
      */
     @CheckReturnValue
@@ -1809,8 +1810,8 @@ public static <T> Maybe<T> unsafeCreate(@NonNull MaybeSource<T> onSubscribe) {
     @NonNull
     public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSupplier,
             @NonNull Function<? super D, ? extends MaybeSource<? extends T>> sourceSupplier,
-            @NonNull Consumer<? super D> resourceDisposer) {
-        return using(resourceSupplier, sourceSupplier, resourceDisposer, true);
+            @NonNull Consumer<? super D> resourceCleanup) {
+        return using(resourceSupplier, sourceSupplier, resourceCleanup, true);
     }
 
     /**
@@ -1832,7 +1833,7 @@ public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSuppl
      *            the factory function to create a resource object that depends on the {@code Maybe}
      * @param sourceSupplier
      *            the factory function to create a {@code MaybeSource}
-     * @param resourceDisposer
+     * @param resourceCleanup
      *            the function that will dispose of the resource
      * @param eager
      *            If {@code true} then resource disposal will happen either on a {@code dispose()} call before the upstream is disposed
@@ -1840,7 +1841,7 @@ public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSuppl
      *            If {@code false} the resource disposal will happen either on a {@code dispose()} call after the upstream is disposed
      *            or just after the emission of a terminal event ({@code onSuccess}, {@code onComplete} or {@code onError}).
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceDisposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceCleanup} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
      */
     @CheckReturnValue
@@ -1848,11 +1849,11 @@ public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSuppl
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSupplier,
             @NonNull Function<? super D, ? extends MaybeSource<? extends T>> sourceSupplier,
-            @NonNull Consumer<? super D> resourceDisposer, boolean eager) {
+            @NonNull Consumer<? super D> resourceCleanup, boolean eager) {
         Objects.requireNonNull(resourceSupplier, "resourceSupplier is null");
         Objects.requireNonNull(sourceSupplier, "sourceSupplier is null");
-        Objects.requireNonNull(resourceDisposer, "resourceDisposer is null");
-        return RxJavaPlugins.onAssembly(new MaybeUsing<T, D>(resourceSupplier, sourceSupplier, resourceDisposer, eager));
+        Objects.requireNonNull(resourceCleanup, "resourceCleanup is null");
+        return RxJavaPlugins.onAssembly(new MaybeUsing<T, D>(resourceSupplier, sourceSupplier, resourceCleanup, eager));
     }
 
     /**
@@ -2678,7 +2679,7 @@ public final Single<T> defaultIfEmpty(@NonNull T defaultItem) {
      *  <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the {@link TimeUnit} in which {@code period} is defined
@@ -2690,8 +2691,8 @@ public final Single<T> defaultIfEmpty(@NonNull T defaultItem) {
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Maybe<T> delay(long delay, @NonNull TimeUnit unit) {
-        return delay(delay, unit, Schedulers.computation());
+    public final Maybe<T> delay(long time, @NonNull TimeUnit unit) {
+        return delay(time, unit, Schedulers.computation());
     }
 
     /**
@@ -2704,7 +2705,7 @@ public final Maybe<T> delay(long delay, @NonNull TimeUnit unit) {
      *  <dd>you specify which {@code Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the time unit of {@code delay}
@@ -2717,10 +2718,10 @@ public final Maybe<T> delay(long delay, @NonNull TimeUnit unit) {
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    public final Maybe<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+    public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
-        return RxJavaPlugins.onAssembly(new MaybeDelay<>(this, Math.max(0L, delay), unit, scheduler));
+        return RxJavaPlugins.onAssembly(new MaybeDelay<>(this, Math.max(0L, time), unit, scheduler));
     }
 
     /**
@@ -2789,7 +2790,7 @@ public final <U> Maybe<T> delaySubscription(@NonNull Publisher<U> subscriptionIn
      *  <dd>This version of {@code delaySubscription} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the time to delay the subscription
      * @param unit
      *            the time unit of {@code delay}
@@ -2801,8 +2802,8 @@ public final <U> Maybe<T> delaySubscription(@NonNull Publisher<U> subscriptionIn
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Maybe<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
-        return delaySubscription(delay, unit, Schedulers.computation());
+    public final Maybe<T> delaySubscription(long time, @NonNull TimeUnit unit) {
+        return delaySubscription(time, unit, Schedulers.computation());
     }
 
     /**
@@ -2815,7 +2816,7 @@ public final Maybe<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the time to delay the subscription
      * @param unit
      *            the time unit of {@code delay}
@@ -2828,8 +2829,8 @@ public final Maybe<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Maybe<T> delaySubscription(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return delaySubscription(Flowable.timer(delay, unit, scheduler));
+    public final Maybe<T> delaySubscription(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delaySubscription(Flowable.timer(time, unit, scheduler));
     }
 
     /**
@@ -3198,21 +3199,21 @@ public final <R> Maybe<R> flatMap(
      *            the type of items emitted by the resulting {@code Maybe}
      * @param mapper
      *            a function that returns a {@code MaybeSource} for the item emitted by the current {@code Maybe}
-     * @param resultSelector
+     * @param combiner
      *            a function that combines one item emitted by each of the source and collection {@code MaybeSource} and
      *            returns an item to be emitted by the resulting {@code MaybeSource}
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code mapper} or {@code resultSelector} is {@code null}
+     * @throws NullPointerException if {@code mapper} or {@code combiner} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public final <U, R> Maybe<R> flatMap(@NonNull Function<? super T, ? extends MaybeSource<? extends U>> mapper,
-            @NonNull BiFunction<? super T, ? super U, ? extends R> resultSelector) {
+            @NonNull BiFunction<? super T, ? super U, ? extends R> combiner) {
         Objects.requireNonNull(mapper, "mapper is null");
-        Objects.requireNonNull(resultSelector, "resultSelector is null");
-        return RxJavaPlugins.onAssembly(new MaybeFlatMapBiSelector<>(this, mapper, resultSelector));
+        Objects.requireNonNull(combiner, "combiner is null");
+        return RxJavaPlugins.onAssembly(new MaybeFlatMapBiSelector<>(this, mapper, combiner));
     }
 
     /**
@@ -3880,19 +3881,19 @@ public final Maybe<T> onErrorComplete(@NonNull Predicate<? super Throwable> pred
      *  <dd>{@code onErrorResumeWith} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param next
+     * @param fallback
      *            the next {@code MaybeSource} that will take over if the current {@code Maybe} encounters
      *            an error
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code next} is {@code null}
+     * @throws NullPointerException if {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Maybe<T> onErrorResumeWith(@NonNull MaybeSource<? extends T> next) {
-        Objects.requireNonNull(next, "next is null");
-        return onErrorResumeNext(Functions.justFunction(next));
+    public final Maybe<T> onErrorResumeWith(@NonNull MaybeSource<? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return onErrorResumeNext(Functions.justFunction(fallback));
     }
 
     /**
@@ -3908,19 +3909,19 @@ public final Maybe<T> onErrorResumeWith(@NonNull MaybeSource<? extends T> next)
      *  <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param resumeFunction
+     * @param fallbackSupplier
      *            a function that returns a {@code MaybeSource} that will take over if the current {@code Maybe} encounters
      *            an error
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code resumeFunction} is {@code null}
+     * @throws NullPointerException if {@code fallbackSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Maybe<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? extends MaybeSource<? extends T>> resumeFunction) {
-        Objects.requireNonNull(resumeFunction, "resumeFunction is null");
-        return RxJavaPlugins.onAssembly(new MaybeOnErrorNext<>(this, resumeFunction));
+    public final Maybe<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? extends MaybeSource<? extends T>> fallbackSupplier) {
+        Objects.requireNonNull(fallbackSupplier, "fallbackSupplier is null");
+        return RxJavaPlugins.onAssembly(new MaybeOnErrorNext<>(this, fallbackSupplier));
     }
 
     /**
@@ -3936,19 +3937,19 @@ public final Maybe<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? e
      *  <dd>{@code onErrorReturn} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param valueSupplier
+     * @param itemSupplier
      *            a function that returns a single value that will be emitted as success value
      *            the current {@code Maybe} signals an {@code onError} event
      * @return the new {@code Maybe} instance
-     * @throws NullPointerException if {@code valueSupplier} is {@code null}
+     * @throws NullPointerException if {@code itemSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Maybe<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> valueSupplier) {
-        Objects.requireNonNull(valueSupplier, "valueSupplier is null");
-        return RxJavaPlugins.onAssembly(new MaybeOnErrorReturn<>(this, valueSupplier));
+    public final Maybe<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> itemSupplier) {
+        Objects.requireNonNull(itemSupplier, "itemSupplier is null");
+        return RxJavaPlugins.onAssembly(new MaybeOnErrorReturn<>(this, itemSupplier));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index 0ea4c18b47..57456a9545 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -1692,20 +1692,20 @@ public static <T> Observable<T> empty() {
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param errorSupplier
+     * @param supplier
      *            a {@link Supplier} factory to return a {@link Throwable} for each individual {@code Observer}
      * @param <T>
      *            the type of the items (ostensibly) emitted by the {@code Observable}
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code errorSupplier} is {@code null}
+     * @throws NullPointerException if {@code supplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Observable<T> error(@NonNull Supplier<? extends Throwable> errorSupplier) {
-        Objects.requireNonNull(errorSupplier, "errorSupplier is null");
-        return RxJavaPlugins.onAssembly(new ObservableError<>(errorSupplier));
+    public static <T> Observable<T> error(@NonNull Supplier<? extends Throwable> supplier) {
+        Objects.requireNonNull(supplier, "supplier is null");
+        return RxJavaPlugins.onAssembly(new ObservableError<>(supplier));
     }
 
     /**
@@ -1718,20 +1718,20 @@ public static <T> Observable<T> error(@NonNull Supplier<? extends Throwable> err
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param exception
+     * @param throwable
      *            the particular {@link Throwable} to pass to {@link Observer#onError onError}
      * @param <T>
      *            the type of the items (ostensibly) emitted by the {@code Observable}
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code exception} is {@code null}
+     * @throws NullPointerException if {@code throwable} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Observable<T> error(@NonNull Throwable exception) {
-        Objects.requireNonNull(exception, "exception is null");
-        return error(Functions.justSupplier(exception));
+    public static <T> Observable<T> error(@NonNull Throwable throwable) {
+        Objects.requireNonNull(throwable, "throwable is null");
+        return error(Functions.justSupplier(throwable));
     }
 
     /**
@@ -4082,9 +4082,10 @@ public static <T> Observable<T> unsafeCreate(@NonNull ObservableSource<T> onSubs
      *            the factory function to create a resource object that depends on the {@code ObservableSource}
      * @param sourceSupplier
      *            the factory function to create an {@code ObservableSource}
-     * @param resourceDisposer
+     * @param resourceCleanup
      *            the function that will dispose of the resource
      * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceCleanup} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
      */
     @CheckReturnValue
@@ -4093,8 +4094,8 @@ public static <T> Observable<T> unsafeCreate(@NonNull ObservableSource<T> onSubs
     public static <T, D> Observable<T> using(
             @NonNull Supplier<? extends D> resourceSupplier,
             @NonNull Function<? super D, ? extends ObservableSource<? extends T>> sourceSupplier,
-            @NonNull Consumer<? super D> resourceDisposer) {
-        return using(resourceSupplier, sourceSupplier, resourceDisposer, true);
+            @NonNull Consumer<? super D> resourceCleanup) {
+        return using(resourceSupplier, sourceSupplier, resourceCleanup, true);
     }
 
     /**
@@ -4114,7 +4115,7 @@ public static <T, D> Observable<T> using(
      *            the factory function to create a resource object that depends on the {@code ObservableSource}
      * @param sourceSupplier
      *            the factory function to create an {@code ObservableSource}
-     * @param resourceDisposer
+     * @param resourceCleanup
      *            the function that will dispose of the resource
      * @param eager
      *            If {@code true}, the resource disposal will happen either on a {@code dispose()} call before the upstream is disposed
@@ -4122,7 +4123,7 @@ public static <T, D> Observable<T> using(
      *            If {@code false}, the resource disposal will happen either on a {@code dispose()} call after the upstream is disposed
      *            or just after the emission of a terminal event ({@code onComplete} or {@code onError}).
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} and {@code resourceDisposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} and {@code resourceCleanup} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
      * @since 2.0
      */
@@ -4132,11 +4133,11 @@ public static <T, D> Observable<T> using(
     public static <T, D> Observable<T> using(
             @NonNull Supplier<? extends D> resourceSupplier,
             @NonNull Function<? super D, ? extends ObservableSource<? extends T>> sourceSupplier,
-            @NonNull Consumer<? super D> resourceDisposer, boolean eager) {
+            @NonNull Consumer<? super D> resourceCleanup, boolean eager) {
         Objects.requireNonNull(resourceSupplier, "resourceSupplier is null");
         Objects.requireNonNull(sourceSupplier, "sourceSupplier is null");
-        Objects.requireNonNull(resourceDisposer, "resourceDisposer is null");
-        return RxJavaPlugins.onAssembly(new ObservableUsing<T, D>(resourceSupplier, sourceSupplier, resourceDisposer, eager));
+        Objects.requireNonNull(resourceCleanup, "resourceCleanup is null");
+        return RxJavaPlugins.onAssembly(new ObservableUsing<T, D>(resourceSupplier, sourceSupplier, resourceCleanup, eager));
     }
 
     /**
@@ -5428,17 +5429,19 @@ public final Iterable<T> blockingLatest() {
      *  <dd>{@code blockingMostRecent} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param initialValue
+     * @param initialItem
      *            the initial value that the {@code Iterable} sequence will yield if the current
      *            {@code Observable} has not yet emitted an item
      * @return the new {@code Iterable} instance
+     * @throws NullPointerException if {@code initialItem} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/first.html">ReactiveX documentation: First</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Iterable<T> blockingMostRecent(@NonNull T initialValue) {
-        return new BlockingObservableMostRecent<>(this, initialValue);
+    public final Iterable<T> blockingMostRecent(@NonNull T initialItem) {
+        Objects.requireNonNull(initialItem, "initialItem is null");
+        return new BlockingObservableMostRecent<>(this, initialItem);
     }
 
     /**
@@ -6236,23 +6239,23 @@ public final <U extends Collection<? super T>> Observable<U> buffer(int count, i
      * @param <U> the collection subclass type to buffer into
      * @param <B>
      *            the boundary value type (ignored)
-     * @param boundary
+     * @param boundaryIndicator
      *            the boundary {@code ObservableSource}
      * @param bufferSupplier
      *            a factory function that returns an instance of the collection subclass to be used and returned
      *            as the buffer
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code boundary} or {@code bufferSupplier} is {@code null}
+     * @throws NullPointerException if {@code boundaryIndicator} or {@code bufferSupplier} is {@code null}
      * @see #buffer(ObservableSource, int)
      * @see <a href="http://reactivex.io/documentation/operators/buffer.html">ReactiveX operators documentation: Buffer</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <B, @NonNull U extends Collection<? super T>> Observable<U> buffer(@NonNull ObservableSource<B> boundary, @NonNull Supplier<U> bufferSupplier) {
-        Objects.requireNonNull(boundary, "boundary is null");
+    public final <B, @NonNull U extends Collection<? super T>> Observable<U> buffer(@NonNull ObservableSource<B> boundaryIndicator, @NonNull Supplier<U> bufferSupplier) {
+        Objects.requireNonNull(boundaryIndicator, "boundaryIndicator is null");
         Objects.requireNonNull(bufferSupplier, "bufferSupplier is null");
-        return RxJavaPlugins.onAssembly(new ObservableBufferExactBoundary<>(this, boundary, bufferSupplier));
+        return RxJavaPlugins.onAssembly(new ObservableBufferExactBoundary<>(this, boundaryIndicator, bufferSupplier));
     }
 
     /**
@@ -6416,22 +6419,22 @@ public final <U> Observable<U> cast(@NonNull Class<U> clazz) {
      * </dl>
      *
      * @param <U> the accumulator and output type
-     * @param initialValueSupplier
+     * @param initialItemSupplier
      *           the mutable data structure that will collect the items
      * @param collector
      *           a function that accepts the {@code state} and an emitted item, and modifies the accumulator accordingly
      *           accordingly
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code initialValueSupplier} or {@code collector} is {@code null}
+     * @throws NullPointerException if {@code initialItemSupplier} or {@code collector} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/reduce.html">ReactiveX operators documentation: Reduce</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <U> Single<U> collect(@NonNull Supplier<? extends U> initialValueSupplier, @NonNull BiConsumer<? super U, ? super T> collector) {
-        Objects.requireNonNull(initialValueSupplier, "initialValueSupplier is null");
+    public final <U> Single<U> collect(@NonNull Supplier<? extends U> initialItemSupplier, @NonNull BiConsumer<? super U, ? super T> collector) {
+        Objects.requireNonNull(initialItemSupplier, "initialItemSupplier is null");
         Objects.requireNonNull(collector, "collector is null");
-        return RxJavaPlugins.onAssembly(new ObservableCollectSingle<>(this, initialValueSupplier, collector));
+        return RxJavaPlugins.onAssembly(new ObservableCollectSingle<>(this, initialItemSupplier, collector));
     }
 
     /**
@@ -6451,21 +6454,21 @@ public final <U> Single<U> collect(@NonNull Supplier<? extends U> initialValueSu
      * </dl>
      *
      * @param <U> the accumulator and output type
-     * @param initialValue
+     * @param initialItem
      *           the mutable data structure that will collect the items
      * @param collector
      *           a function that accepts the {@code state} and an emitted item, and modifies the accumulator accordingly
      *           accordingly
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code initialValue} or {@code collector} is {@code null}
+     * @throws NullPointerException if {@code initialItem} or {@code collector} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/reduce.html">ReactiveX operators documentation: Reduce</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <U> Single<U> collectInto(@NonNull U initialValue, @NonNull BiConsumer<? super U, ? super T> collector) {
-        Objects.requireNonNull(initialValue, "initialValue is null");
-        return collect(Functions.justSupplier(initialValue), collector);
+    public final <U> Single<U> collectInto(@NonNull U initialItem, @NonNull BiConsumer<? super U, ? super T> collector) {
+        Objects.requireNonNull(initialItem, "initialItem is null");
+        return collect(Functions.justSupplier(initialItem), collector);
     }
 
     /**
@@ -7454,18 +7457,18 @@ public final Observable<T> concatWith(@NonNull CompletableSource other) {
      *  <dd>{@code contains} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param element
+     * @param item
      *            the item to search for in the emissions from the current {@code Observable}
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code element} is {@code null}
+     * @throws NullPointerException if {@code item} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/contains.html">ReactiveX operators documentation: Contains</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Single<Boolean> contains(@NonNull Object element) {
-        Objects.requireNonNull(element, "element is null");
-        return any(Functions.equalsWith(element));
+    public final Single<Boolean> contains(@NonNull Object item) {
+        Objects.requireNonNull(item, "item is null");
+        return any(Functions.equalsWith(item));
     }
 
     /**
@@ -7509,18 +7512,18 @@ public final Single<Long> count() {
      *
      * @param <U>
      *            the debounce value type (ignored)
-     * @param debounceSelector
+     * @param debounceIndicator
      *            function to return a sequence that indicates the throttle duration for each item via its own emission or completion
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code debounceSelector} is {@code null}
+     * @throws NullPointerException if {@code debounceIndicator} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/debounce.html">ReactiveX operators documentation: Debounce</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <U> Observable<T> debounce(@NonNull Function<? super T, ? extends ObservableSource<U>> debounceSelector) {
-        Objects.requireNonNull(debounceSelector, "debounceSelector is null");
-        return RxJavaPlugins.onAssembly(new ObservableDebounce<>(this, debounceSelector));
+    public final <U> Observable<T> debounce(@NonNull Function<? super T, ? extends ObservableSource<U>> debounceIndicator) {
+        Objects.requireNonNull(debounceIndicator, "debounceIndicator is null");
+        return RxJavaPlugins.onAssembly(new ObservableDebounce<>(this, debounceIndicator));
     }
 
     /**
@@ -7644,20 +7647,20 @@ public final Observable<T> defaultIfEmpty(@NonNull T defaultItem) {
      *
      * @param <U>
      *            the item delay value type (ignored)
-     * @param itemDelay
+     * @param itemDelayIndicator
      *            a function that returns an {@code ObservableSource} for each item emitted by the current {@code Observable}, which is
      *            then used to delay the emission of that item by the resulting {@code Observable} until the {@code ObservableSource}
      *            returned from {@code itemDelay} emits an item
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code itemDelay} is {@code null}
+     * @throws NullPointerException if {@code itemDelayIndicator} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <U> Observable<T> delay(@NonNull Function<? super T, ? extends ObservableSource<U>> itemDelay) {
-        Objects.requireNonNull(itemDelay, "itemDelay is null");
-        return flatMap(ObservableInternalHelper.itemDelay(itemDelay));
+    public final <U> Observable<T> delay(@NonNull Function<? super T, ? extends ObservableSource<U>> itemDelayIndicator) {
+        Objects.requireNonNull(itemDelayIndicator, "itemDelayIndicator is null");
+        return flatMap(ObservableInternalHelper.itemDelay(itemDelayIndicator));
     }
 
     /**
@@ -7670,7 +7673,7 @@ public final <U> Observable<T> delay(@NonNull Function<? super T, ? extends Obse
      *  <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the {@link TimeUnit} in which {@code period} is defined
@@ -7683,8 +7686,8 @@ public final <U> Observable<T> delay(@NonNull Function<? super T, ? extends Obse
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Observable<T> delay(long delay, @NonNull TimeUnit unit) {
-        return delay(delay, unit, Schedulers.computation(), false);
+    public final Observable<T> delay(long time, @NonNull TimeUnit unit) {
+        return delay(time, unit, Schedulers.computation(), false);
     }
 
     /**
@@ -7697,7 +7700,7 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit) {
      *  <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the {@link TimeUnit} in which {@code period} is defined
@@ -7712,8 +7715,8 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit) {
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Observable<T> delay(long delay, @NonNull TimeUnit unit, boolean delayError) {
-        return delay(delay, unit, Schedulers.computation(), delayError);
+    public final Observable<T> delay(long time, @NonNull TimeUnit unit, boolean delayError) {
+        return delay(time, unit, Schedulers.computation(), delayError);
     }
 
     /**
@@ -7726,7 +7729,7 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit, boolean del
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the time unit of {@code delay}
@@ -7739,8 +7742,8 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit, boolean del
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Observable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return delay(delay, unit, scheduler, false);
+    public final Observable<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delay(time, unit, scheduler, false);
     }
 
     /**
@@ -7753,7 +7756,7 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Sc
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the delay to shift the source by
      * @param unit
      *            the time unit of {@code delay}
@@ -7769,11 +7772,11 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Sc
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Observable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
+    public final Observable<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
 
-        return RxJavaPlugins.onAssembly(new ObservableDelay<>(this, delay, unit, scheduler, delayError));
+        return RxJavaPlugins.onAssembly(new ObservableDelay<>(this, time, unit, scheduler, delayError));
     }
 
     /**
@@ -7793,23 +7796,23 @@ public final Observable<T> delay(long delay, @NonNull TimeUnit unit, @NonNull Sc
      *            the subscription delay value type (ignored)
      * @param <V>
      *            the item delay value type (ignored)
-     * @param subscriptionDelay
+     * @param subscriptionIndicator
      *            a function that returns an {@code ObservableSource} that triggers the subscription to the current {@code Observable}
      *            once it emits any item
-     * @param itemDelay
+     * @param itemDelayIndicator
      *            a function that returns an {@code ObservableSource} for each item emitted by the current {@code Observable}, which is
      *            then used to delay the emission of that item by the resulting {@code Observable} until the {@code ObservableSource}
      *            returned from {@code itemDelay} emits an item
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code subscriptionDelay} or {@code itemDelay} is {@code null}
+     * @throws NullPointerException if {@code subscriptionIndicator} or {@code itemDelayIndicator} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <U, V> Observable<T> delay(@NonNull ObservableSource<U> subscriptionDelay,
-            @NonNull Function<? super T, ? extends ObservableSource<V>> itemDelay) {
-        return delaySubscription(subscriptionDelay).delay(itemDelay);
+    public final <U, V> Observable<T> delay(@NonNull ObservableSource<U> subscriptionIndicator,
+            @NonNull Function<? super T, ? extends ObservableSource<V>> itemDelayIndicator) {
+        return delaySubscription(subscriptionIndicator).delay(itemDelayIndicator);
     }
 
     /**
@@ -7823,18 +7826,18 @@ public final <U, V> Observable<T> delay(@NonNull ObservableSource<U> subscriptio
      * </dl>
      *
      * @param <U> the value type of the other {@code Observable}, irrelevant
-     * @param other the other {@code ObservableSource} that should trigger the subscription
+     * @param subscriptionIndicator the other {@code ObservableSource} that should trigger the subscription
      *        to the current {@code Observable}.
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code other} is {@code null}
+     * @throws NullPointerException if {@code subscriptionIndicator} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <U> Observable<T> delaySubscription(@NonNull ObservableSource<U> other) {
-        Objects.requireNonNull(other, "other is null");
-        return RxJavaPlugins.onAssembly(new ObservableDelaySubscriptionOther<>(this, other));
+    public final <U> Observable<T> delaySubscription(@NonNull ObservableSource<U> subscriptionIndicator) {
+        Objects.requireNonNull(subscriptionIndicator, "subscriptionIndicator is null");
+        return RxJavaPlugins.onAssembly(new ObservableDelaySubscriptionOther<>(this, subscriptionIndicator));
     }
 
     /**
@@ -7846,7 +7849,7 @@ public final <U> Observable<T> delaySubscription(@NonNull ObservableSource<U> ot
      *  <dd>This version of {@code delaySubscription} operates by default on the {@code computation} {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the time to delay the subscription
      * @param unit
      *            the time unit of {@code delay}
@@ -7857,8 +7860,8 @@ public final <U> Observable<T> delaySubscription(@NonNull ObservableSource<U> ot
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Observable<T> delaySubscription(long delay, @NonNull TimeUnit unit) {
-        return delaySubscription(delay, unit, Schedulers.computation());
+    public final Observable<T> delaySubscription(long time, @NonNull TimeUnit unit) {
+        return delaySubscription(time, unit, Schedulers.computation());
     }
 
     /**
@@ -7871,7 +7874,7 @@ public final Observable<T> delaySubscription(long delay, @NonNull TimeUnit unit)
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
      * </dl>
      *
-     * @param delay
+     * @param time
      *            the time to delay the subscription
      * @param unit
      *            the time unit of {@code delay}
@@ -7884,8 +7887,8 @@ public final Observable<T> delaySubscription(long delay, @NonNull TimeUnit unit)
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Observable<T> delaySubscription(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
-        return delaySubscription(timer(delay, unit, scheduler));
+    public final Observable<T> delaySubscription(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delaySubscription(timer(time, unit, scheduler));
     }
 
     /**
@@ -10366,19 +10369,19 @@ public final <U> Observable<U> ofType(@NonNull Class<U> clazz) {
      *  <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param resumeFunction
+     * @param fallbackSupplier
      *            a function that returns an {@code ObservableSource} that will take over if the current {@code Observable} encounters
      *            an error
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code resumeFunction} is {@code null}
+     * @throws NullPointerException if {@code fallbackSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Observable<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? extends ObservableSource<? extends T>> resumeFunction) {
-        Objects.requireNonNull(resumeFunction, "resumeFunction is null");
-        return RxJavaPlugins.onAssembly(new ObservableOnErrorNext<>(this, resumeFunction));
+    public final Observable<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? extends ObservableSource<? extends T>> fallbackSupplier) {
+        Objects.requireNonNull(fallbackSupplier, "fallbackSupplier is null");
+        return RxJavaPlugins.onAssembly(new ObservableOnErrorNext<>(this, fallbackSupplier));
     }
 
     /**
@@ -10404,19 +10407,19 @@ public final Observable<T> onErrorResumeNext(@NonNull Function<? super Throwable
      *  <dd>{@code onErrorResumeWith} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param next
+     * @param fallback
      *            the next {@code ObservableSource} source that will take over if the current {@code Observable} encounters
      *            an error
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code next} is {@code null}
+     * @throws NullPointerException if {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Observable<T> onErrorResumeWith(@NonNull ObservableSource<? extends T> next) {
-        Objects.requireNonNull(next, "next is null");
-        return onErrorResumeNext(Functions.justFunction(next));
+    public final Observable<T> onErrorResumeWith(@NonNull ObservableSource<? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return onErrorResumeNext(Functions.justFunction(fallback));
     }
 
     /**
@@ -10439,19 +10442,19 @@ public final Observable<T> onErrorResumeWith(@NonNull ObservableSource<? extends
      *  <dd>{@code onErrorReturn} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param valueSupplier
+     * @param itemSupplier
      *            a function that returns a single value that will be emitted along with a regular {@code onComplete} in case
      *            the current {@code Observable} signals an {@code onError} event
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code valueSupplier} is {@code null}
+     * @throws NullPointerException if {@code itemSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Observable<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> valueSupplier) {
-        Objects.requireNonNull(valueSupplier, "valueSupplier is null");
-        return RxJavaPlugins.onAssembly(new ObservableOnErrorReturn<>(this, valueSupplier));
+    public final Observable<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> itemSupplier) {
+        Objects.requireNonNull(itemSupplier, "itemSupplier is null");
+        return RxJavaPlugins.onAssembly(new ObservableOnErrorReturn<>(this, itemSupplier));
     }
 
     /**
@@ -12488,18 +12491,18 @@ public final Observable<T> sorted() {
      *  <dd>{@code sorted} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param sortFunction
+     * @param comparator
      *            a function that compares two items emitted by the current {@code Observable} and returns an {@code int}
      *            that indicates their sort order
-     * @throws NullPointerException if {@code sortFunction} is {@code null}
+     * @throws NullPointerException if {@code comparator} is {@code null}
      * @return the new {@code Observable} instance
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Observable<T> sorted(@NonNull Comparator<? super T> sortFunction) {
-        Objects.requireNonNull(sortFunction, "sortFunction is null");
-        return toList().toObservable().map(Functions.listSorter(sortFunction)).flatMapIterable(Functions.identity());
+    public final Observable<T> sorted(@NonNull Comparator<? super T> comparator) {
+        Objects.requireNonNull(comparator, "comparator is null");
+        return toList().toObservable().map(Functions.listSorter(comparator)).flatMapIterable(Functions.identity());
     }
 
     /**
@@ -14130,19 +14133,19 @@ public final <V> Observable<T> timeout(@NonNull Function<? super T, ? extends Ob
      * @param itemTimeoutIndicator
      *            a function that returns an {@code ObservableSource}, for each item emitted by the current {@code Observable}, that
      *            determines the timeout window for the subsequent item
-     * @param other
+     * @param fallback
      *            the fallback {@code ObservableSource} to switch to if the current {@code Observable} times out
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code itemTimeoutIndicator} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code itemTimeoutIndicator} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public final <V> Observable<T> timeout(@NonNull Function<? super T, ? extends ObservableSource<V>> itemTimeoutIndicator,
-            @NonNull ObservableSource<? extends T> other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(null, itemTimeoutIndicator, other);
+            @NonNull ObservableSource<? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(null, itemTimeoutIndicator, fallback);
     }
 
     /**
@@ -14187,18 +14190,18 @@ public final Observable<T> timeout(long timeout, @NonNull TimeUnit unit) {
      *            maximum duration between items before a timeout occurs
      * @param unit
      *            the unit of time that applies to the {@code timeout} argument
-     * @param other
+     * @param fallback
      *            the fallback {@code ObservableSource} to use in case of a timeout
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code unit} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
-    public final Observable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull ObservableSource<? extends T> other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(timeout, unit, other, Schedulers.computation());
+    public final Observable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull ObservableSource<? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(timeout, unit, fallback, Schedulers.computation());
     }
 
     /**
@@ -14219,18 +14222,18 @@ public final Observable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNul
      *            the unit of time that applies to the {@code timeout} argument
      * @param scheduler
      *            the {@code Scheduler} to run the timeout timers on
-     * @param other
+     * @param fallback
      *            the {@code ObservableSource} to use as the fallback in case of a timeout
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code other} is {@code null}
+     * @throws NullPointerException if {@code unit}, {@code scheduler} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.CUSTOM)
     @NonNull
-    public final Observable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull ObservableSource<? extends T> other) {
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(timeout, unit, other, scheduler);
+    public final Observable<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull ObservableSource<? extends T> fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(timeout, unit, fallback, scheduler);
     }
 
     /**
@@ -14319,11 +14322,11 @@ public final <U, V> Observable<T> timeout(@NonNull ObservableSource<U> firstTime
      *            a function that returns an {@code ObservableSource} for each item emitted by the current {@code Observable} and that
      *            determines the timeout window in which the subsequent source item must arrive in order to
      *            continue the sequence
-     * @param other
+     * @param fallback
      *            the fallback {@code ObservableSource} to switch to if the current {@code Observable} times out
      * @return the new {@code Observable} instance
      * @throws NullPointerException
-     *             if {@code firstTimeoutIndicator}, {@code itemTimeoutIndicator} or {@code other} is {@code null}
+     *             if {@code firstTimeoutIndicator}, {@code itemTimeoutIndicator} or {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
      */
     @CheckReturnValue
@@ -14332,28 +14335,28 @@ public final <U, V> Observable<T> timeout(@NonNull ObservableSource<U> firstTime
     public final <U, V> Observable<T> timeout(
             @NonNull ObservableSource<U> firstTimeoutIndicator,
             @NonNull Function<? super T, ? extends ObservableSource<V>> itemTimeoutIndicator,
-            @NonNull ObservableSource<? extends T> other) {
+            @NonNull ObservableSource<? extends T> fallback) {
         Objects.requireNonNull(firstTimeoutIndicator, "firstTimeoutIndicator is null");
-        Objects.requireNonNull(other, "other is null");
-        return timeout0(firstTimeoutIndicator, itemTimeoutIndicator, other);
+        Objects.requireNonNull(fallback, "fallback is null");
+        return timeout0(firstTimeoutIndicator, itemTimeoutIndicator, fallback);
     }
 
     @NonNull
     private Observable<T> timeout0(long timeout, @NonNull TimeUnit unit,
-            @Nullable ObservableSource<? extends T> other,
+            @Nullable ObservableSource<? extends T> fallback,
             @NonNull Scheduler scheduler) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
-        return RxJavaPlugins.onAssembly(new ObservableTimeoutTimed<>(this, timeout, unit, scheduler, other));
+        return RxJavaPlugins.onAssembly(new ObservableTimeoutTimed<>(this, timeout, unit, scheduler, fallback));
     }
 
     @NonNull
     private <U, V> Observable<T> timeout0(
             @NonNull ObservableSource<U> firstTimeoutIndicator,
             @NonNull Function<? super T, ? extends ObservableSource<V>> itemTimeoutIndicator,
-            @Nullable ObservableSource<? extends T> other) {
+            @Nullable ObservableSource<? extends T> fallback) {
         Objects.requireNonNull(itemTimeoutIndicator, "itemTimeoutIndicator is null");
-        return RxJavaPlugins.onAssembly(new ObservableTimeout<>(this, firstTimeoutIndicator, itemTimeoutIndicator, other));
+        return RxJavaPlugins.onAssembly(new ObservableTimeout<>(this, firstTimeoutIndicator, itemTimeoutIndicator, fallback));
     }
 
     /**
@@ -15538,17 +15541,17 @@ public final Observable<Observable<T>> window(
      *
      * @param <B>
      *            the window element type (ignored)
-     * @param boundary
+     * @param boundaryIndicator
      *            an {@code ObservableSource} whose emitted items close and open windows
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code boundary} is {@code null}
+     * @throws NullPointerException if {@code boundaryIndicator} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/window.html">ReactiveX operators documentation: Window</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <B> Observable<Observable<T>> window(@NonNull ObservableSource<B> boundary) {
-        return window(boundary, bufferSize());
+    public final <B> Observable<Observable<T>> window(@NonNull ObservableSource<B> boundaryIndicator) {
+        return window(boundaryIndicator, bufferSize());
     }
 
     /**
@@ -15569,22 +15572,22 @@ public final <B> Observable<Observable<T>> window(@NonNull ObservableSource<B> b
      *
      * @param <B>
      *            the window element type (ignored)
-     * @param boundary
+     * @param boundaryIndicator
      *            an {@code ObservableSource} whose emitted items close and open windows
      * @param bufferSize
      *            the capacity hint for the buffer in the inner windows
      * @return the new {@code Observable} instance
-     * @throws NullPointerException if {@code boundary} is {@code null}
+     * @throws NullPointerException if {@code boundaryIndicator} is {@code null}
      * @throws IllegalArgumentException if {@code bufferSize} is non-positive
      * @see <a href="http://reactivex.io/documentation/operators/window.html">ReactiveX operators documentation: Window</a>
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final <B> Observable<Observable<T>> window(@NonNull ObservableSource<B> boundary, int bufferSize) {
-        Objects.requireNonNull(boundary, "boundary is null");
+    public final <B> Observable<Observable<T>> window(@NonNull ObservableSource<B> boundaryIndicator, int bufferSize) {
+        Objects.requireNonNull(boundaryIndicator, "boundaryIndicator is null");
         ObjectHelper.verifyPositive(bufferSize, "bufferSize");
-        return RxJavaPlugins.onAssembly(new ObservableWindowBoundary<>(this, boundary, bufferSize));
+        return RxJavaPlugins.onAssembly(new ObservableWindowBoundary<>(this, boundaryIndicator, bufferSize));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index eb90b83fcb..0541ce8657 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -557,17 +557,17 @@ public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends S
      * <dd>{@code defer} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the value type
-     * @param singleSupplier the {@code Supplier} that is called for each individual {@code SingleObserver} and
+     * @param supplier the {@code Supplier} that is called for each individual {@code SingleObserver} and
      * returns a {@code SingleSource} instance to subscribe to
-     * @throws NullPointerException if {@code singleSupplier} is {@code null}
+     * @throws NullPointerException if {@code supplier} is {@code null}
      * @return the new {@code Single} instance
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Single<T> defer(@NonNull Supplier<? extends SingleSource<? extends T>> singleSupplier) {
-        Objects.requireNonNull(singleSupplier, "singleSupplier is null");
-        return RxJavaPlugins.onAssembly(new SingleDefer<>(singleSupplier));
+    public static <T> Single<T> defer(@NonNull Supplier<? extends SingleSource<? extends T>> supplier) {
+        Objects.requireNonNull(supplier, "supplier is null");
+        return RxJavaPlugins.onAssembly(new SingleDefer<>(supplier));
     }
 
     /**
@@ -579,17 +579,17 @@ public static <T> Single<T> defer(@NonNull Supplier<? extends SingleSource<? ext
      * <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the value type
-     * @param errorSupplier the {@link Supplier} that is called for each individual {@code SingleObserver} and
+     * @param supplier the {@link Supplier} that is called for each individual {@code SingleObserver} and
      * returns a {@code Throwable} instance to be emitted.
-     * @throws NullPointerException if {@code errorSupplier} is {@code null}
+     * @throws NullPointerException if {@code supplier} is {@code null}
      * @return the new {@code Single} instance
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Single<T> error(@NonNull Supplier<? extends Throwable> errorSupplier) {
-        Objects.requireNonNull(errorSupplier, "errorSupplier is null");
-        return RxJavaPlugins.onAssembly(new SingleError<>(errorSupplier));
+    public static <T> Single<T> error(@NonNull Supplier<? extends Throwable> supplier) {
+        Objects.requireNonNull(supplier, "supplier is null");
+        return RxJavaPlugins.onAssembly(new SingleError<>(supplier));
     }
 
     /**
@@ -602,21 +602,21 @@ public static <T> Single<T> error(@NonNull Supplier<? extends Throwable> errorSu
      * <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param exception
+     * @param throwable
      *            the particular {@link Throwable} to pass to {@link SingleObserver#onError onError}
      * @param <T>
      *            the type of the item (ostensibly) emitted by the {@code Single}
      * @return the new {@code Single} that invokes the subscriber's {@link SingleObserver#onError onError} method when
      *         the subscriber subscribes to it
-     * @throws NullPointerException if {@code exception} is {@code null}
+     * @throws NullPointerException if {@code throwable} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Single<T> error(@NonNull Throwable exception) {
-        Objects.requireNonNull(exception, "exception is null");
-        return error(Functions.justSupplier(exception));
+    public static <T> Single<T> error(@NonNull Throwable throwable) {
+        Objects.requireNonNull(throwable, "throwable is null");
+        return error(Functions.justSupplier(throwable));
     }
 
     /**
@@ -782,18 +782,18 @@ public static <T> Single<T> fromPublisher(@NonNull Publisher<@NonNull ? extends
      *   <dd>{@code fromObservable} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param observableSource the source sequence to wrap, not {@code null}
+     * @param observable the source sequence to wrap, not {@code null}
      * @param <T>
      *         the type of the item emitted by the {@code Single}.
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code observableSource} is {@code null}
+     * @throws NullPointerException if {@code observable} is {@code null}
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Single<T> fromObservable(@NonNull ObservableSource<? extends T> observableSource) {
-        Objects.requireNonNull(observableSource, "observableSource is null");
-        return RxJavaPlugins.onAssembly(new ObservableSingleSingle<>(observableSource, null));
+    public static <T> Single<T> fromObservable(@NonNull ObservableSource<? extends T> observable) {
+        Objects.requireNonNull(observable, "observable is null");
+        return RxJavaPlugins.onAssembly(new ObservableSingleSingle<>(observable, null));
     }
 
     /**
@@ -1446,22 +1446,23 @@ public static <T> Single<T> unsafeCreate(@NonNull SingleSource<T> onSubscribe) {
      * @param <T> the value type of the {@code SingleSource} generated
      * @param <U> the resource type
      * @param resourceSupplier the {@link Supplier} called for each {@link SingleObserver} to generate a resource object
-     * @param singleFunction the function called with the returned resource
+     * @param sourceSupplier the function called with the returned resource
      *                  object from {@code resourceSupplier} and should return a {@code SingleSource} instance
      *                  to be run by the operator
-     * @param disposer the consumer of the generated resource that is called exactly once for
+     * @param resourceCleanup the consumer of the generated resource that is called exactly once for
      *                  that particular resource when the generated {@code SingleSource} terminates
      *                  (successfully or with an error) or gets disposed.
      * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} and {@code resourceCleanup} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public static <T, U> Single<T> using(@NonNull Supplier<U> resourceSupplier,
-            @NonNull Function<? super U, ? extends SingleSource<? extends T>> singleFunction,
-            @NonNull Consumer<? super U> disposer) {
-        return using(resourceSupplier, singleFunction, disposer, true);
+            @NonNull Function<? super U, ? extends SingleSource<? extends T>> sourceSupplier,
+            @NonNull Consumer<? super U> resourceCleanup) {
+        return using(resourceSupplier, sourceSupplier, resourceCleanup, true);
     }
 
     /**
@@ -1476,10 +1477,10 @@ public static <T, U> Single<T> using(@NonNull Supplier<U> resourceSupplier,
      * @param <T> the value type of the {@code SingleSource} generated
      * @param <U> the resource type
      * @param resourceSupplier the {@link Supplier} called for each {@link SingleObserver} to generate a resource object
-     * @param singleFunction the function called with the returned resource
+     * @param sourceSupplier the function called with the returned resource
      *                  object from {@code resourceSupplier} and should return a {@code SingleSource} instance
      *                  to be run by the operator
-     * @param disposer the consumer of the generated resource that is called exactly once for
+     * @param resourceCleanup the consumer of the generated resource that is called exactly once for
      *                  that particular resource when the generated {@code SingleSource} terminates
      *                  (successfully or with an error) or gets disposed.
      * @param eager
@@ -1488,7 +1489,7 @@ public static <T, U> Single<T> using(@NonNull Supplier<U> resourceSupplier,
      *            If {@code false} the resource disposal will happen either on a {@code dispose()} call after the upstream is disposed
      *            or just after the emission of a terminal event ({@code onSuccess} or {@code onError}).
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code resourceSupplier}, {@code singleFunction} or {@code disposer} is {@code null}
+     * @throws NullPointerException if {@code resourceSupplier}, {@code sourceSupplier} or {@code resourceCleanup} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
@@ -1496,14 +1497,14 @@ public static <T, U> Single<T> using(@NonNull Supplier<U> resourceSupplier,
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T, U> Single<T> using(
             @NonNull Supplier<U> resourceSupplier,
-            @NonNull Function<? super U, ? extends SingleSource<? extends T>> singleFunction,
-            @NonNull Consumer<? super U> disposer,
+            @NonNull Function<? super U, ? extends SingleSource<? extends T>> sourceSupplier,
+            @NonNull Consumer<? super U> resourceCleanup,
             boolean eager) {
         Objects.requireNonNull(resourceSupplier, "resourceSupplier is null");
-        Objects.requireNonNull(singleFunction, "singleFunction is null");
-        Objects.requireNonNull(disposer, "disposer is null");
+        Objects.requireNonNull(sourceSupplier, "sourceSupplier is null");
+        Objects.requireNonNull(resourceCleanup, "resourceCleanup is null");
 
-        return RxJavaPlugins.onAssembly(new SingleUsing<>(resourceSupplier, singleFunction, disposer, eager));
+        return RxJavaPlugins.onAssembly(new SingleUsing<>(resourceSupplier, sourceSupplier, resourceCleanup, eager));
     }
 
     /**
@@ -2297,18 +2298,18 @@ public final Single<T> delay(long time, @NonNull TimeUnit unit, @NonNull Schedul
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code delaySubscription} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param other the {@code CompletableSource} that has to complete before the subscription to the
+     * @param subscriptionIndicator the {@code CompletableSource} that has to complete before the subscription to the
      *              current {@code Single} happens
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code other} is {@code null}
+     * @throws NullPointerException if {@code subscriptionIndicator} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Single<T> delaySubscription(@NonNull CompletableSource other) {
-        Objects.requireNonNull(other, "other is null");
-        return RxJavaPlugins.onAssembly(new SingleDelayWithCompletable<>(this, other));
+    public final Single<T> delaySubscription(@NonNull CompletableSource subscriptionIndicator) {
+        Objects.requireNonNull(subscriptionIndicator, "subscriptionIndicator is null");
+        return RxJavaPlugins.onAssembly(new SingleDelayWithCompletable<>(this, subscriptionIndicator));
     }
 
     /**
@@ -2323,18 +2324,18 @@ public final Single<T> delaySubscription(@NonNull CompletableSource other) {
      * <dd>{@code delaySubscription} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <U> the element type of the other source
-     * @param other the {@code SingleSource} that has to complete before the subscription to the
+     * @param subscriptionIndicator the {@code SingleSource} that has to complete before the subscription to the
      *              current {@code Single} happens
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code other} is {@code null}
+     * @throws NullPointerException if {@code subscriptionIndicator} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final <U> Single<T> delaySubscription(@NonNull SingleSource<U> other) {
-        Objects.requireNonNull(other, "other is null");
-        return RxJavaPlugins.onAssembly(new SingleDelayWithSingle<>(this, other));
+    public final <U> Single<T> delaySubscription(@NonNull SingleSource<U> subscriptionIndicator) {
+        Objects.requireNonNull(subscriptionIndicator, "subscriptionIndicator is null");
+        return RxJavaPlugins.onAssembly(new SingleDelayWithSingle<>(this, subscriptionIndicator));
     }
 
     /**
@@ -2349,18 +2350,18 @@ public final <U> Single<T> delaySubscription(@NonNull SingleSource<U> other) {
      * <dd>{@code delaySubscription} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <U> the element type of the other source
-     * @param other the {@code ObservableSource} that has to signal a value or complete before the
+     * @param subscriptionIndicator the {@code ObservableSource} that has to signal a value or complete before the
      *              subscription to the current {@code Single} happens
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code other} is {@code null}
+     * @throws NullPointerException if {@code subscriptionIndicator} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final <U> Single<T> delaySubscription(@NonNull ObservableSource<U> other) {
-        Objects.requireNonNull(other, "other is null");
-        return RxJavaPlugins.onAssembly(new SingleDelayWithObservable<>(this, other));
+    public final <U> Single<T> delaySubscription(@NonNull ObservableSource<U> subscriptionIndicator) {
+        Objects.requireNonNull(subscriptionIndicator, "subscriptionIndicator is null");
+        return RxJavaPlugins.onAssembly(new SingleDelayWithObservable<>(this, subscriptionIndicator));
     }
 
     /**
@@ -2379,19 +2380,19 @@ public final <U> Single<T> delaySubscription(@NonNull ObservableSource<U> other)
      * <dd>{@code delaySubscription} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <U> the element type of the other source
-     * @param other the {@code Publisher} that has to signal a value or complete before the
+     * @param subscriptionIndicator the {@code Publisher} that has to signal a value or complete before the
      *              subscription to the current {@code Single} happens
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code other} is {@code null}
+     * @throws NullPointerException if {@code subscriptionIndicator} is {@code null}
      * @since 2.0
      */
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final <U> Single<T> delaySubscription(@NonNull Publisher<U> other) {
-        Objects.requireNonNull(other, "other is null");
-        return RxJavaPlugins.onAssembly(new SingleDelayWithPublisher<>(this, other));
+    public final <U> Single<T> delaySubscription(@NonNull Publisher<U> subscriptionIndicator) {
+        Objects.requireNonNull(subscriptionIndicator, "subscriptionIndicator is null");
+        return RxJavaPlugins.onAssembly(new SingleDelayWithPublisher<>(this, subscriptionIndicator));
     }
 
     /**
@@ -3154,15 +3155,16 @@ public final Single<Notification<T>> materialize() {
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code contains} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param value the value to compare against the success value of this {@code Single}
+     * @param item the value to compare against the success value of this {@code Single}
      * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code item} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public final Single<Boolean> contains(@NonNull Object value) {
-        return contains(value, ObjectHelper.equalsPredicate());
+    public final Single<Boolean> contains(@NonNull Object item) {
+        return contains(item, ObjectHelper.equalsPredicate());
     }
 
     /**
@@ -3174,20 +3176,20 @@ public final Single<Boolean> contains(@NonNull Object value) {
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code contains} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param value the value to compare against the success value of this {@code Single}
+     * @param item the value to compare against the success value of this {@code Single}
      * @param comparer the function that receives the success value of this {@code Single}, the value provided
      *                 and should return {@code true} if they are considered equal
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code value} or {@code comparer} is {@code null}
+     * @throws NullPointerException if {@code item} or {@code comparer} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Single<Boolean> contains(@NonNull Object value, @NonNull BiPredicate<Object, Object> comparer) {
-        Objects.requireNonNull(value, "value is null");
+    public final Single<Boolean> contains(@NonNull Object item, @NonNull BiPredicate<Object, Object> comparer) {
+        Objects.requireNonNull(item, "item is null");
         Objects.requireNonNull(comparer, "comparer is null");
-        return RxJavaPlugins.onAssembly(new SingleContains<>(this, value, comparer));
+        return RxJavaPlugins.onAssembly(new SingleContains<>(this, item, comparer));
     }
 
     /**
@@ -3264,19 +3266,19 @@ public final Single<T> observeOn(@NonNull Scheduler scheduler) {
      * <dd>{@code onErrorReturn} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param resumeFunction
+     * @param itemSupplier
      *            a function that returns an item that the new {@code Single} will emit if the current {@code Single} encounters
      *            an error
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code resumeFunction} is {@code null}
+     * @throws NullPointerException if {@code itemSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Single<T> onErrorReturn(@NonNull Function<Throwable, ? extends T> resumeFunction) {
-        Objects.requireNonNull(resumeFunction, "resumeFunction is null");
-        return RxJavaPlugins.onAssembly(new SingleOnErrorReturn<>(this, resumeFunction, null));
+    public final Single<T> onErrorReturn(@NonNull Function<Throwable, ? extends T> itemSupplier) {
+        Objects.requireNonNull(itemSupplier, "itemSupplier is null");
+        return RxJavaPlugins.onAssembly(new SingleOnErrorReturn<>(this, itemSupplier, null));
     }
 
     /**
@@ -3287,17 +3289,17 @@ public final Single<T> onErrorReturn(@NonNull Function<Throwable, ? extends T> r
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code onErrorReturnItem} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * @param value the value to signal if the current {@code Single} fails
+     * @param item the value to signal if the current {@code Single} fails
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code value} is {@code null}
+     * @throws NullPointerException if {@code item} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final Single<T> onErrorReturnItem(@NonNull T value) {
-        Objects.requireNonNull(value, "value is null");
-        return RxJavaPlugins.onAssembly(new SingleOnErrorReturn<>(this, null, value));
+    public final Single<T> onErrorReturnItem(@NonNull T item) {
+        Objects.requireNonNull(item, "item is null");
+        return RxJavaPlugins.onAssembly(new SingleOnErrorReturn<>(this, null, item));
     }
 
     /**
@@ -3359,9 +3361,9 @@ public final Single<T> onErrorResumeWith(@NonNull SingleSource<? extends T> fall
      * <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
-     * @param fallback a function that returns a {@code Single} that will take control if source {@code Single} encounters an error.
+     * @param fallbackSupplier a function that returns a {@code SingleSource} that will take control if source {@code Single} encounters an error.
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code fallback} is {@code null}
+     * @throws NullPointerException if {@code fallbackSupplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
      * @since .20
      */
@@ -3369,9 +3371,9 @@ public final Single<T> onErrorResumeWith(@NonNull SingleSource<? extends T> fall
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public final Single<T> onErrorResumeNext(
-            @NonNull Function<? super Throwable, ? extends SingleSource<? extends T>> fallback) {
-        Objects.requireNonNull(fallback, "fallback is null");
-        return RxJavaPlugins.onAssembly(new SingleResumeNext<>(this, fallback));
+            @NonNull Function<? super Throwable, ? extends SingleSource<? extends T>> fallbackSupplier) {
+        Objects.requireNonNull(fallbackSupplier, "fallbackSupplier is null");
+        return RxJavaPlugins.onAssembly(new SingleResumeNext<>(this, fallbackSupplier));
     }
 
     /**
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/BlockingFlowableMostRecentTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/BlockingFlowableMostRecentTest.java
index f652e9fbf6..82ae58730f 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/BlockingFlowableMostRecentTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/BlockingFlowableMostRecentTest.java
@@ -26,10 +26,6 @@
 import io.reactivex.rxjava3.schedulers.TestScheduler;
 
 public class BlockingFlowableMostRecentTest extends RxJavaTest {
-    @Test
-    public void mostRecentNull() {
-        assertNull(Flowable.<Void>never().blockingMostRecent(null).iterator().next());
-    }
 
     @Test
     public void mostRecent() {
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/BlockingObservableMostRecentTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/BlockingObservableMostRecentTest.java
index 6ffd920f24..cc04638ee7 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/BlockingObservableMostRecentTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/BlockingObservableMostRecentTest.java
@@ -27,10 +27,6 @@
 import io.reactivex.rxjava3.subjects.*;
 
 public class BlockingObservableMostRecentTest extends RxJavaTest {
-    @Test
-    public void mostRecentNull() {
-        assertNull(Observable.<Void>never().blockingMostRecent(null).iterator().next());
-    }
 
     static <T> Iterable<T> mostRecent(Observable<T> source, T initialValue) {
         return source.blockingMostRecent(initialValue);
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorArgumentNaming.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorArgumentNaming.java
new file mode 100644
index 0000000000..727b522d05
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorArgumentNaming.java
@@ -0,0 +1,169 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.util;
+
+import java.lang.reflect.*;
+import java.util.*;
+
+import org.reactivestreams.*;
+
+import com.google.common.base.Strings;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.core.Observer;
+import io.reactivex.rxjava3.core.Observable;
+
+/**
+ * Compare method argument naming across base classes.
+ * This is not a full test because some naming mismatch is legitimate, such as singular in Maybe/Single and
+ * plural in Flowable/Observable
+ */
+public final class OperatorArgumentNaming {
+
+    private OperatorArgumentNaming() {
+        throw new IllegalStateException("No instances!");
+    }
+
+    /** Classes to compare with each other. */
+    static final Class<?>[] CLASSES = { Flowable.class, Observable.class, Maybe.class, Single.class, Completable.class };
+
+    /** Types that refer to a reactive type and is generally matching the parent class; for comparison, these have to be unified. */
+    static final Set<Class<?>> BASE_TYPE_SET = new HashSet<>(Arrays.asList(
+            Flowable.class, Publisher.class, Subscriber.class, FlowableSubscriber.class,
+            Observable.class, ObservableSource.class, Observer.class,
+            Maybe.class, MaybeSource.class, MaybeObserver.class,
+            Single.class, SingleSource.class, SingleObserver.class,
+            Completable.class, CompletableSource.class, CompletableObserver.class
+    ));
+
+    public static void main(String[] args) {
+        // className -> methodName -> overloads -> arguments
+        Map<String, Map<String, List<List<ArgumentNameAndType>>>> map = new HashMap<>();
+
+        for (Class<?> clazz : CLASSES) {
+            Map<String, List<List<ArgumentNameAndType>>> classMethods = map.computeIfAbsent(clazz.getSimpleName(), v -> new HashMap<>());
+            for (Method method : clazz.getDeclaredMethods()) {
+                if (method.getDeclaringClass() == clazz && method.getParameterCount() != 0) {
+                    List<List<ArgumentNameAndType>> overloads = classMethods.computeIfAbsent(method.getName(), v -> new ArrayList<>());
+
+                    List<ArgumentNameAndType> overload = new ArrayList<>();
+                    overloads.add(overload);
+
+                    for (Parameter param : method.getParameters()) {
+                        String typeName;
+                        Class<?> type = param.getType();
+                        if (type.isArray()) {
+                            Class<?> componentType = type.getComponentType();
+                            if (BASE_TYPE_SET.contains(componentType)) {
+                                typeName = "BaseType";
+                            } else {
+                                typeName = type.getComponentType().getSimpleName() + "[]";
+                            }
+                        } else
+                        if (BASE_TYPE_SET.contains(type)) {
+                            typeName = "BaseType";
+                        } else {
+                            typeName = type.getSimpleName();
+                        }
+                        String name = param.getName();
+                        if (name.equals("bufferSize") || name.equals("prefetch") || name.equals("capacityHint")) {
+                            name = "bufferSize|prefetch|capacityHint";
+                        }
+                        if (name.equals("subscriber") || name.equals("observer")) {
+                            name = "subscriber|observer";
+                        }
+                        if (name.contains("onNext")) {
+                            name = name.replace("onNext", "onNext|onSuccess");
+                        } else
+                        if (name.contains("onSuccess")) {
+                            name = name.replace("onSuccess", "onNext|onSuccess");
+                        }
+                        overload.add(new ArgumentNameAndType(typeName, name));
+                    }
+                }
+            }
+        }
+
+        int counter = 0;
+
+        for (int i = 0; i < CLASSES.length - 1; i++) {
+            String firstName = CLASSES[i].getSimpleName();
+            Map<String, List<List<ArgumentNameAndType>>> firstClassMethods = map.get(firstName);
+            for (int j = i + 1; j < CLASSES.length; j++) {
+                String secondName = CLASSES[j].getSimpleName();
+                Map<String, List<List<ArgumentNameAndType>>> secondClassMethods = map.get(secondName);
+
+                for (Map.Entry<String, List<List<ArgumentNameAndType>>> methodOverloadsFirst : firstClassMethods.entrySet()) {
+
+                    List<List<ArgumentNameAndType>> methodOverloadsSecond = secondClassMethods.get(methodOverloadsFirst.getKey());
+
+                    if (methodOverloadsSecond != null) {
+                        for (List<ArgumentNameAndType> overloadFirst : methodOverloadsFirst.getValue()) {
+                            for (List<ArgumentNameAndType> overloadSecond : methodOverloadsSecond) {
+                                if (overloadFirst.size() == overloadSecond.size()) {
+                                    // Argument types match?
+                                    boolean match = true;
+                                    for (int k = 0; k < overloadFirst.size(); k++) {
+                                        if (!overloadFirst.get(k).type.equals(overloadSecond.get(k).type)) {
+                                            match = false;
+                                            break;
+                                        }
+                                    }
+                                    // Argument names match?
+                                    if (match) {
+                                        for (int k = 0; k < overloadFirst.size(); k++) {
+                                            if (!overloadFirst.get(k).name.equals(overloadSecond.get(k).name)) {
+                                                System.out.print("Argument naming mismatch #");
+                                                System.out.println(++counter);
+
+                                                System.out.print("  ");
+                                                System.out.print(Strings.padEnd(firstName, Math.max(firstName.length(), secondName.length()) + 1, ' '));
+                                                System.out.print(methodOverloadsFirst.getKey());
+                                                System.out.print("  ");
+                                                System.out.println(overloadFirst);
+
+                                                System.out.print("  ");
+                                                System.out.print(Strings.padEnd(secondName, Math.max(firstName.length(), secondName.length()) + 1, ' '));
+                                                System.out.print(methodOverloadsFirst.getKey());
+                                                System.out.print("  ");
+                                                System.out.println(overloadSecond);
+                                                System.out.println();
+                                                break;
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    static final class ArgumentNameAndType {
+        final String type;
+        final String name;
+
+        ArgumentNameAndType(String type, String name) {
+            this.type = type;
+            this.name = name;
+        }
+
+        @Override
+        public String toString() {
+            return type + " " + name;
+        }
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java
index f9becca37c..403a83964a 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java
@@ -142,9 +142,6 @@ public void checkParallelFlowable() {
         addOverride(new ParamOverride(Flowable.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Scheduler.class));
         addOverride(new ParamOverride(Flowable.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Scheduler.class, Boolean.TYPE));
 
-        // null default is allowed
-        addOverride(new ParamOverride(Flowable.class, 0, ParamMode.ANY, "blockingMostRecent", Object.class));
-
         // negative time is considered as zero time
         addOverride(new ParamOverride(Flowable.class, 0, ParamMode.ANY, "delaySubscription", Long.TYPE, TimeUnit.class));
         addOverride(new ParamOverride(Flowable.class, 0, ParamMode.ANY, "delaySubscription", Long.TYPE, TimeUnit.class, Scheduler.class));
@@ -390,9 +387,6 @@ public void checkParallelFlowable() {
         addOverride(new ParamOverride(Observable.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Scheduler.class));
         addOverride(new ParamOverride(Observable.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Scheduler.class, Boolean.TYPE));
 
-        // null default is allowed
-        addOverride(new ParamOverride(Observable.class, 0, ParamMode.ANY, "blockingMostRecent", Object.class));
-
         // negative time is considered as zero time
         addOverride(new ParamOverride(Observable.class, 0, ParamMode.ANY, "delaySubscription", Long.TYPE, TimeUnit.class));
         addOverride(new ParamOverride(Observable.class, 0, ParamMode.ANY, "delaySubscription", Long.TYPE, TimeUnit.class, Scheduler.class));
diff --git a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
index fe6d215165..ba307d394d 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
@@ -203,7 +203,7 @@ static void processFile(Class<?> clazz) throws Exception {
 
                     int quote = line.indexOf('"', comma);
 
-                    String message = line.substring(quote + 1, quote + 2 + paramName.length());
+                    String message = line.substring(quote + 1, Math.min(line.length(), quote + 2 + paramName.length()));
 
                     if (line.contains("\"A Disposable")) {
                         continue;

From 13ffa189bb16149eec7a2fe23c03c5b35037f737 Mon Sep 17 00:00:00 2001
From: slisaasquatch <slisaasquatch@users.noreply.github.com>
Date: Tue, 21 Jan 2020 13:21:08 -0800
Subject: [PATCH 02/37] Rename Single.equals to Single.sequenceEqual (#6856)

* Rename Single.equals to Single.sequenceEqual

* Rename Single.sequenceEqual arguments

* Update mentions of renamed parameters
---
 .../java/io/reactivex/rxjava3/core/Single.java   | 16 ++++++++--------
 .../operators/single/SingleEqualsTest.java       |  2 +-
 .../operators/single/SingleMiscTest.java         |  4 ++--
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 0541ce8657..f915bdc5b2 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -1387,22 +1387,22 @@ public static Single<Long> timer(long delay, @NonNull TimeUnit unit, @NonNull Sc
      * <img width="640" height="465" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.equals.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
-     * <dd>{@code equals} does not operate by default on a particular {@link Scheduler}.</dd>
+     * <dd>{@code sequenceEqual} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the common value type
-     * @param first the first {@code SingleSource} instance
-     * @param second the second {@code SingleSource} instance
+     * @param source1 the first {@code SingleSource} instance
+     * @param source2 the second {@code SingleSource} instance
      * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code first} or {@code second} is {@code null}
+     * @throws NullPointerException if {@code source1} or {@code source2} is {@code null}
      * @since 2.0
      */
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Single<Boolean> equals(@NonNull SingleSource<? extends T> first, @NonNull SingleSource<? extends T> second) { // NOPMD
-        Objects.requireNonNull(first, "first is null");
-        Objects.requireNonNull(second, "second is null");
-        return RxJavaPlugins.onAssembly(new SingleEquals<>(first, second));
+    public static <T> Single<Boolean> sequenceEqual(@NonNull SingleSource<? extends T> source1, @NonNull SingleSource<? extends T> source2) { // NOPMD
+        Objects.requireNonNull(source1, "source1 is null");
+        Objects.requireNonNull(source2, "source2 is null");
+        return RxJavaPlugins.onAssembly(new SingleEquals<>(source1, source2));
     }
 
     /**
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleEqualsTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleEqualsTest.java
index c664784869..6c1bf14f30 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleEqualsTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleEqualsTest.java
@@ -28,7 +28,7 @@ public class SingleEqualsTest extends RxJavaTest {
     public void bothError() {
         List<Throwable> errors = TestHelper.trackPluginErrors();
         try {
-            Single.equals(Single.error(new TestException("One")), Single.error(new TestException("Two")))
+            Single.sequenceEqual(Single.error(new TestException("One")), Single.error(new TestException("Two")))
             .to(TestHelper.<Boolean>testConsumer())
             .assertFailureAndMessage(TestException.class, "One");
 
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMiscTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMiscTest.java
index ca2ccacdc2..dad1322b22 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMiscTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMiscTest.java
@@ -280,11 +280,11 @@ public void toObservable() {
 
     @Test
     public void equals() {
-        Single.equals(Single.just(1), Single.just(1).hide())
+        Single.sequenceEqual(Single.just(1), Single.just(1).hide())
         .test()
         .assertResult(true);
 
-        Single.equals(Single.just(1), Single.just(2))
+        Single.sequenceEqual(Single.just(1), Single.just(2))
         .test()
         .assertResult(false);
     }

From b6aceec436ee1dcc9ff904bb14be6698f65130e7 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Wed, 22 Jan 2020 14:03:30 +0100
Subject: [PATCH 03/37] 3.x: Verify the use of base interfaces in operator
 inputs & lambdas (#6858)

* 3.x: Verify the use of base interfaces in operator inputs & lambdas

* Add @NonNull annotations too.
---
 .../io/reactivex/rxjava3/core/Flowable.java   |   4 +-
 .../validators/OperatorsUseInterfaces.java    | 189 ++++++++++++++++++
 2 files changed, 191 insertions(+), 2 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/validators/OperatorsUseInterfaces.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 038c3f680b..5f5aff68c6 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -6790,7 +6790,7 @@ public final Flowable<List<T>> buffer(long timespan, @NonNull TimeUnit unit, @No
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public final <TOpening, TClosing> Flowable<List<T>> buffer(
-            @NonNull Flowable<? extends TOpening> openingIndicator,
+            @NonNull Publisher<@NonNull ? extends TOpening> openingIndicator,
             @NonNull Function<? super TOpening, ? extends Publisher<@NonNull ? extends TClosing>> closingIndicator) {
         return buffer(openingIndicator, closingIndicator, ArrayListSupplier.asSupplier());
     }
@@ -6831,7 +6831,7 @@ public final <TOpening, TClosing> Flowable<List<T>> buffer(
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public final <TOpening, TClosing, U extends Collection<? super T>> Flowable<U> buffer(
-            @NonNull Flowable<? extends TOpening> openingIndicator,
+            @NonNull Publisher<@NonNull ? extends TOpening> openingIndicator,
             @NonNull Function<? super TOpening, ? extends Publisher<@NonNull ? extends TClosing>> closingIndicator,
             @NonNull Supplier<U> bufferSupplier) {
         Objects.requireNonNull(openingIndicator, "openingIndicator is null");
diff --git a/src/test/java/io/reactivex/rxjava3/validators/OperatorsUseInterfaces.java b/src/test/java/io/reactivex/rxjava3/validators/OperatorsUseInterfaces.java
new file mode 100644
index 0000000000..e521c15b6e
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/validators/OperatorsUseInterfaces.java
@@ -0,0 +1,189 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.validators;
+
+import static org.junit.Assert.*;
+
+import java.lang.reflect.*;
+import java.util.*;
+import java.util.Observable;
+import java.util.concurrent.Callable;
+
+import org.junit.Test;
+import org.reactivestreams.Publisher;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.parallel.ParallelFlowable;
+
+/**
+ * Verify that an operator method uses base interfaces as its direct input or
+ * has lambdas returning base interfaces.
+ */
+public class OperatorsUseInterfaces {
+
+    @Test
+    public void checkFlowable() {
+        checkClass(Flowable.class);
+    }
+
+    @Test
+    public void checkObservable() {
+        checkClass(Observable.class);
+    }
+
+    @Test
+    public void checkMaybe() {
+        checkClass(Maybe.class);
+    }
+
+    @Test
+    public void checkSingle() {
+        checkClass(Single.class);
+    }
+
+    @Test
+    public void checkCompletable() {
+        checkClass(Completable.class);
+    }
+
+    @Test
+    public void checkParallelFlowable() {
+        checkClass(ParallelFlowable.class);
+    }
+
+    void checkClass(Class<?> clazz) {
+        StringBuilder error = new StringBuilder();
+        int errors = 0;
+
+        for (Method method : clazz.getMethods()) {
+            if (method.getDeclaringClass() == clazz) {
+                int pidx = 1;
+                for (Parameter param : method.getParameters()) {
+                    Class<?> type = param.getType();
+                    if (type.isArray()) {
+                        type = type.getComponentType();
+                    }
+                    if (CLASSES.contains(type)) {
+                        errors++;
+                        error.append("Non-interface input parameter #")
+                        .append(pidx)
+                        .append(": ")
+                        .append(type)
+                        .append("\r\n")
+                        .append("    ")
+                        .append(method)
+                        .append("\r\n")
+                        ;
+                    }
+                    if (CAN_RETURN.contains(type)) {
+                        Type gtype = method.getGenericParameterTypes()[pidx - 1];
+                        if (gtype instanceof GenericArrayType) {
+                            gtype = ((GenericArrayType)gtype).getGenericComponentType();
+                        }
+                        ParameterizedType ptype = (ParameterizedType)gtype;
+                        for (;;) {
+                            Type[] parameterArgTypes = ptype.getActualTypeArguments();
+                            Type argType = parameterArgTypes[parameterArgTypes.length - 1];
+                            if (argType instanceof GenericArrayType) {
+                                argType = ((GenericArrayType)argType).getGenericComponentType();
+                            }
+                            if (argType instanceof ParameterizedType) {
+                                ParameterizedType lastArg = (ParameterizedType)argType;
+
+                                if (CLASSES.contains(lastArg.getRawType())) {
+                                    errors++;
+                                    error.append("Non-interface lambda return #")
+                                    .append(pidx)
+                                    .append(": ")
+                                    .append(type)
+                                    .append("\r\n")
+                                    .append("    ")
+                                    .append(method)
+                                    .append("\r\n")
+                                    ;
+                                }
+
+                                if (CAN_RETURN.contains(lastArg.getRawType())) {
+                                    ptype = lastArg;
+                                    continue;
+                                }
+                            }
+                            break;
+                        }
+                    }
+                    pidx++;
+                }
+            }
+        }
+
+        if (errors != 0) {
+            error.insert(0, "Found " + errors + " issues\r\n");
+            fail(error.toString());
+        }
+    }
+
+    public void method1(Flowable<?> f) {
+        // self-test
+    }
+
+    public void method2(Callable<Flowable<?>> c) {
+        // self-test
+    }
+
+    public void method3(Supplier<Publisher<Flowable<?>>> c) {
+        // self-test
+    }
+
+    public void method4(Flowable<?>[] array) {
+        // self-test
+    }
+
+    public void method5(Callable<Flowable<?>[]> c) {
+        // self-test
+    }
+
+    public void method6(Callable<Publisher<Flowable<?>[]>> c) {
+        // self-test
+    }
+
+    @Test
+    public void checkSelf() {
+        try {
+            checkClass(OperatorsUseInterfaces.class);
+            throw new RuntimeException("Should have failed");
+        } catch (AssertionError expected) {
+            assertTrue(expected.toString(), expected.toString().contains("method1"));
+            assertTrue(expected.toString(), expected.toString().contains("method2"));
+            assertTrue(expected.toString(), expected.toString().contains("method3"));
+            assertTrue(expected.toString(), expected.toString().contains("method4"));
+            assertTrue(expected.toString(), expected.toString().contains("method5"));
+            assertTrue(expected.toString(), expected.toString().contains("method6"));
+        }
+    }
+
+    static final Set<Class<?>> CLASSES = new HashSet<>(Arrays.asList(
+            Flowable.class, Observable.class,
+            Maybe.class, Single.class,
+            Completable.class
+    ));
+
+    static final Set<Class<?>> CAN_RETURN = new HashSet<>(Arrays.asList(
+            Callable.class, Supplier.class,
+            Function.class, BiFunction.class, Function3.class, Function4.class,
+            Function5.class, Function6.class, Function7.class, Function8.class,
+            Function9.class,
+            Publisher.class, ObservableSource.class, MaybeSource.class, SingleSource.class
+    ));
+}

From 99de2aa77c9b29620177397190ded1211e4fc772 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Wed, 22 Jan 2020 14:03:53 +0100
Subject: [PATCH 04/37] 3.x: [Wiki] Improve Operator-Matrix with links and
 notes (#6857)

---
 docs/Operator-Matrix.md                       | 587 +++++++++++-------
 .../util/OperatorMatrixGenerator.java         | 385 +++++++++++-
 2 files changed, 727 insertions(+), 245 deletions(-)

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index ded48d8509..832d64311d 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -1,240 +1,347 @@
-Operator | `Flowable` | `Observable` | `Maybe` | `Single` | `Completable` |
------|:---:|:---:|:---:|:---:|:---:|
-`all`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`amb`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`ambArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`ambWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`andThen`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`any`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingAwait`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`blockingFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingForEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingGet`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingMostRecent`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`blockingSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`buffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`cache`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`cacheWithInitialCapacity`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`cast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`collect`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`collectInto`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`combineLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`combineLatestArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`combineLatestArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`combineLatestDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`complete`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`compose`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`concat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`concatArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`concatArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatArrayEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`concatWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`contains`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`create`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`defer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`delay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`delaySubscription`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doAfterTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doFinally`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doOnError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doOnSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`doOnTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`equals`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`error`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`fromAction`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`fromCallable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromCompletable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`fromCompletionStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`fromMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromRunnable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`fromSupplier`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`groupBy`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`groupJoin`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`hide`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`ignoreElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`just`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`lift`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`map`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`materialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`merge`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`mergeArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`mergeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`mergeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`observeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onErrorComplete`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`onErrorResumeNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`onTerminateDetach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`repeat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`repeatUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`repeatWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`retry`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`subscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`subscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`subscribeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`takeUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`test`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`timeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`timer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`toList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`toMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toMultimap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`toSortedList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`unsafeCreate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`unsubscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`using`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`window`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`withLatestFrom`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`wrap`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmatrix-flowable.png) | ![Observable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmatrix-observable.png) | ![Maybe](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmatrix-maybe.png) | ![Single](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmatrix-single.png) | ![Completable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmatrix-completable.png) |
+-----|---|---|---|---|---|
+<a name='all'></a>`all`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use contains().'>([1](#notes-1))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use contains().'>([1](#notes-1))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='amb'></a>`amb`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='ambArray'></a>`ambArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='ambWith'></a>`ambWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='andThen'></a>`andThen`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatWith.'>([3](#notes-3))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatWith.'>([3](#notes-3))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatWith.'>([3](#notes-3))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatWith.'>([3](#notes-3))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='any'></a>`any`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use contains().'>([1](#notes-1))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use contains().'>([1](#notes-1))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='blockingAwait'></a>`blockingAwait`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingFirst().'>([4](#notes-4))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingFirst().'>([4](#notes-4))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingGet().'>([5](#notes-5))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingGet().'>([5](#notes-5))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='blockingFirst'></a>`blockingFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingForEach'></a>`blockingForEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingSubscribe()'>([8](#notes-8))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingSubscribe()'>([8](#notes-8))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingSubscribe()'>([8](#notes-8))</sup>|
+<a name='blockingGet'></a>`blockingGet`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingFirst().'>([4](#notes-4))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use blockingFirst().'>([4](#notes-4))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingIterable'></a>`blockingIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingLast'></a>`blockingLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingLatest'></a>`blockingLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingMostRecent'></a>`blockingMostRecent`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingNext'></a>`blockingNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingSingle'></a>`blockingSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingStream'></a>`blockingStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
+<a name='blockingSubscribe'></a>`blockingSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='buffer'></a>`buffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a list/collection.'>([9](#notes-9))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a list/collection.'>([10](#notes-10))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a list/collection.'>([11](#notes-11))</sup>|
+<a name='cache'></a>`cache`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='cacheWithInitialCapacity'></a>`cacheWithInitialCapacity`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to store. Use cache().'>([12](#notes-12))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to store. Use cache().'>([12](#notes-12))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to store. Use cache().'>([12](#notes-12))</sup>|
+<a name='cast'></a>`cast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='collect'></a>`collect`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
+<a name='collectInto'></a>`collectInto`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
+<a name='combineLatest'></a>`combineLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use merge().'>([17](#notes-17))</sup>|
+<a name='combineLatestArray'></a>`combineLatestArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zipArray().'>([18](#notes-18))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zipArray().'>([18](#notes-18))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use mergeArray().'>([19](#notes-19))</sup>|
+<a name='combineLatestArrayDelayError'></a>`combineLatestArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zipArray().'>([18](#notes-18))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zipArray().'>([18](#notes-18))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use mergeArrayDelayError().'>([20](#notes-20))</sup>|
+<a name='combineLatestDelayError'></a>`combineLatestDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use mergeDelayError().'>([21](#notes-21))</sup>|
+<a name='complete'></a>`complete`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use empty().'>([22](#notes-22))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use empty().'>([22](#notes-22))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use empty().'>([22](#notes-22))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='compose'></a>`compose`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='concat'></a>`concat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='concatArray'></a>`concatArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='concatArrayDelayError'></a>`concatArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatArrayEager'></a>`concatArrayEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArray().'>([24](#notes-24))</sup>|
+<a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
+<a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatEager'></a>`concatEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use merge().'>([26](#notes-26))</sup>|
+<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapCompletableDelayError'></a>`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapDelayError'></a>`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatWith'></a>`concatWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='contains'></a>`contains`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([31](#notes-31))</sup>|
+<a name='create'></a>`create`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
+<a name='defer'></a>`defer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='delay'></a>`delay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='delaySubscription'></a>`delaySubscription`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([37](#notes-37))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doAfterTerminate'></a>`doAfterTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doFinally'></a>`doFinally`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|
+<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([39](#notes-39))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([40](#notes-40))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([41](#notes-41))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([41](#notes-41))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doOnError'></a>`doOnError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([42](#notes-42))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
+<a name='doOnSubscribe'></a>`doOnSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([45](#notes-45))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doOnTerminate'></a>`doOnTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([49](#notes-49))</sup>|
+<a name='equals'></a>`equals`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='error'></a>`error`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
+<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([54](#notes-54))</sup>|
+<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([56](#notes-56))</sup>|
+<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|
+<a name='flatMap'></a>`flatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapCompletable'></a>`flatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([58](#notes-58))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([59](#notes-59))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapSingleElement'></a>`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([60](#notes-60))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|
+<a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|
+<a name='fromAction'></a>`fromAction`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromArray'></a>`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='fromCallable'></a>`fromCallable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromCompletable'></a>`fromCompletable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([68](#notes-68))</sup>|
+<a name='fromCompletionStage'></a>`fromCompletionStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromFuture'></a>`fromFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromIterable'></a>`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='fromMaybe'></a>`fromMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromObservable'></a>`fromObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromOptional'></a>`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='fromPublisher'></a>`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromRunnable'></a>`fromRunnable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromSingle'></a>`fromSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromStream'></a>`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='fromSupplier'></a>`fromSupplier`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='generate'></a>`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([69](#notes-69))</sup>|
+<a name='groupBy'></a>`groupBy`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to group.'>([71](#notes-71))</sup>|
+<a name='groupJoin'></a>`groupJoin`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([72](#notes-72))</sup>|
+<a name='hide'></a>`hide`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='ignoreElement'></a>`ignoreElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='ignoreElements'></a>`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='interval'></a>`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|
+<a name='intervalRange'></a>`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|
+<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='join'></a>`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([76](#notes-76))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([76](#notes-76))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([72](#notes-72))</sup>|
+<a name='just'></a>`just`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
+<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([54](#notes-54))</sup>|
+<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([56](#notes-56))</sup>|
+<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|
+<a name='lift'></a>`lift`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='map'></a>`map`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='mapOptional'></a>`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='materialize'></a>`materialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='merge'></a>`merge`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeArray'></a>`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeArrayDelayError'></a>`mergeArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeDelayError'></a>`mergeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeWith'></a>`mergeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='never'></a>`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='observeOn'></a>`observeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([77](#notes-77))</sup>|
+<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
+<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
+<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
+<a name='onErrorComplete'></a>`onErrorComplete`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='onErrorResumeNext'></a>`onErrorResumeNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='onErrorResumeWith'></a>`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='onErrorReturn'></a>`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='onErrorReturnItem'></a>`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='onTerminateDetach'></a>`onTerminateDetach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='parallel'></a>`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|
+<a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
+<a name='range'></a>`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='rangeLong'></a>`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
+<a name='reduce'></a>`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
+<a name='reduceWith'></a>`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
+<a name='repeat'></a>`repeat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='repeatUntil'></a>`repeatUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='repeatWhen'></a>`repeatWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='replay'></a>`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
+<a name='retry'></a>`retry`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='retryWhen'></a>`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
+<a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
+<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|
+<a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
+<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
+<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([54](#notes-54))</sup>|
+<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([56](#notes-56))</sup>|
+<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|
+<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
+<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
+<a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([86](#notes-86))</sup>|
+<a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|
+<a name='startWith'></a>`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='startWithArray'></a>`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([88](#notes-88))</sup>|
+<a name='startWithItem'></a>`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([89](#notes-89))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([89](#notes-89))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([89](#notes-89))</sup>|
+<a name='startWithIterable'></a>`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([90](#notes-90))</sup>|
+<a name='subscribe'></a>`subscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='subscribeOn'></a>`subscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='subscribeWith'></a>`subscribeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='switchIfEmpty'></a>`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use defaultIfEmpty().'>([91](#notes-91))</sup>|
+<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
+<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
+<a name='takeUntil'></a>`takeUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='takeWhile'></a>`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='test'></a>`test`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='timeout'></a>`timeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='timer'></a>`timer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([93](#notes-93))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='toList'></a>`toList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
+<a name='toMap'></a>`toMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
+<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toMultimap'></a>`toMultimap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
+<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSortedList'></a>`toSortedList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
+<a name='unsafeCreate'></a>`unsafeCreate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='unsubscribeOn'></a>`unsubscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='using'></a>`using`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='window'></a>`window`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([99](#notes-99))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a nested source.'>([101](#notes-101))</sup>|
+<a name='withLatestFrom'></a>`withLatestFrom`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use merge().'>([17](#notes-17))</sup>|
+<a name='wrap'></a>`wrap`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromPublisher().'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([103](#notes-103))</sup>|
+<a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([104](#notes-104))</sup>|
+<a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([105](#notes-105))</sup>|
+
+#### Notes
+<a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
+<a name='notes-2'></a><sup>2</sup> Always empty.<br/>
+<a name='notes-3'></a><sup>3</sup> Use [`concatWith`](#concatWith).<br/>
+<a name='notes-4'></a><sup>4</sup> Use [`blockingFirst()`](#blockingFirst), [`blockingSingle()`](#blockingSingle) or [`blockingLast()`](#blockingLast).<br/>
+<a name='notes-5'></a><sup>5</sup> Use [`blockingGet()`](#blockingGet).<br/>
+<a name='notes-6'></a><sup>6</sup> At most one element to get. Use [`blockingGet()`](#blockingGet).<br/>
+<a name='notes-7'></a><sup>7</sup> No elements to get. Use [`blockingAwait()`](#blockingAwait).<br/>
+<a name='notes-8'></a><sup>8</sup> Use [`blockingSubscribe()`](#blockingSubscribe)<br/>
+<a name='notes-9'></a><sup>9</sup> Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.<br/>
+<a name='notes-10'></a><sup>10</sup> Use [`map()`](#map) to transform into a list/collection.<br/>
+<a name='notes-11'></a><sup>11</sup> Always empty. Use [`andThen()`](#andThen) to bring in a list/collection.<br/>
+<a name='notes-12'></a><sup>12</sup> At most one element to store. Use [`cache()`](#cache).<br/>
+<a name='notes-13'></a><sup>13</sup> At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.<br/>
+<a name='notes-14'></a><sup>14</sup> One element to collect. Use [`map()`](#map) to transform into a list/collection.<br/>
+<a name='notes-15'></a><sup>15</sup> Always empty. Use [`andThen()`](#andThen) to bring in a collection.<br/>
+<a name='notes-16'></a><sup>16</sup> At most one element per source. Use [`zip()`](#zip).<br/>
+<a name='notes-17'></a><sup>17</sup> Always empty. Use [`merge()`](#merge).<br/>
+<a name='notes-18'></a><sup>18</sup> At most one element per source. Use [`zipArray()`](#zipArray).<br/>
+<a name='notes-19'></a><sup>19</sup> Always empty. Use [`mergeArray()`](#mergeArray).<br/>
+<a name='notes-20'></a><sup>20</sup> Always empty. Use [`mergeArrayDelayError()`](#mergeArrayDelayError).<br/>
+<a name='notes-21'></a><sup>21</sup> Always empty. Use [`mergeDelayError()`](#mergeDelayError).<br/>
+<a name='notes-22'></a><sup>22</sup> Use [`empty()`](#empty).<br/>
+<a name='notes-23'></a><sup>23</sup> Never empty.<br/>
+<a name='notes-24'></a><sup>24</sup> No items to keep ordered. Use [`mergeArray()`](#mergeArray).<br/>
+<a name='notes-25'></a><sup>25</sup> No items to keep ordered. Use [`mergeArrayDelayError()`](#mergeArrayDelayError).<br/>
+<a name='notes-26'></a><sup>26</sup> No items to keep ordered. Use [`merge()`](#merge).<br/>
+<a name='notes-27'></a><sup>27</sup> Always empty thus no items to map.<br/>
+<a name='notes-28'></a><sup>28</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
+<a name='notes-29'></a><sup>29</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
+<a name='notes-30'></a><sup>30</sup> Never empty thus always 1.<br/>
+<a name='notes-31'></a><sup>31</sup> Always empty thus always 0.<br/>
+<a name='notes-32'></a><sup>32</sup> At most one item signaled so no subsequent items to work with.<br/>
+<a name='notes-33'></a><sup>33</sup> Always empty thus no items to work with.<br/>
+<a name='notes-34'></a><sup>34</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
+<a name='notes-35'></a><sup>35</sup> At most one item, always distinct.<br/>
+<a name='notes-36'></a><sup>36</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
+<a name='notes-37'></a><sup>37</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
+<a name='notes-38'></a><sup>38</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
+<a name='notes-39'></a><sup>39</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
+<a name='notes-40'></a><sup>40</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
+<a name='notes-41'></a><sup>41</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
+<a name='notes-42'></a><sup>42</sup> Use [`doOnEach()`](#doOnEach).<br/>
+<a name='notes-43'></a><sup>43</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
+<a name='notes-44'></a><sup>44</sup> Backpressure related and not supported outside `Flowable`.<br/>
+<a name='notes-45'></a><sup>45</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
+<a name='notes-46'></a><sup>46</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-47'></a><sup>47</sup> Always one item with index 0.<br/>
+<a name='notes-48'></a><sup>48</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
+<a name='notes-49'></a><sup>49</sup> Use [`complete()`](#complete).<br/>
+<a name='notes-50'></a><sup>50</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-51'></a><sup>51</sup> Always one item.<br/>
+<a name='notes-52'></a><sup>52</sup> At most one item, would be no-op.<br/>
+<a name='notes-53'></a><sup>53</sup> Always one item, would be no-op.<br/>
+<a name='notes-54'></a><sup>54</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
+<a name='notes-55'></a><sup>55</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-56'></a><sup>56</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-57'></a><sup>57</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
+<a name='notes-58'></a><sup>58</sup> Use [`flatMap`](#flatMap).<br/>
+<a name='notes-59'></a><sup>59</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
+<a name='notes-60'></a><sup>60</sup> Use [`flatMapSingle`](#flatMapSingle).<br/>
+<a name='notes-61'></a><sup>61</sup> Use [`flatMapIterable()`](#flatMapIterable).<br/>
+<a name='notes-62'></a><sup>62</sup> Use [`flatMapStream()`](#flatMapStream).<br/>
+<a name='notes-63'></a><sup>63</sup> Use [`subscribe()`](#subscribe).<br/>
+<a name='notes-64'></a><sup>64</sup> At most one item. Use [`just()`](#just) or [`empty()`](#empty).<br/>
+<a name='notes-65'></a><sup>65</sup> Always one item. Use [`just()`](#just).<br/>
+<a name='notes-66'></a><sup>66</sup> Always empty. Use [`complete()`](#complete).<br/>
+<a name='notes-67'></a><sup>67</sup> Always error.<br/>
+<a name='notes-68'></a><sup>68</sup> Use [`wrap()`](#wrap).<br/>
+<a name='notes-69'></a><sup>69</sup> Use [`fromSupplier()`](#fromSupplier).<br/>
+<a name='notes-70'></a><sup>70</sup> At most one item.<br/>
+<a name='notes-71'></a><sup>71</sup> Always empty thus no items to group.<br/>
+<a name='notes-72'></a><sup>72</sup> Always empty thus no items to join.<br/>
+<a name='notes-73'></a><sup>73</sup> Use [`ignoreElements()`](#ignoreElements).<br/>
+<a name='notes-74'></a><sup>74</sup> Use [`ignoreElement()`](#ignoreElement).<br/>
+<a name='notes-75'></a><sup>75</sup> At most one item. Use [`timer()`](#timer).<br/>
+<a name='notes-76'></a><sup>76</sup> At most one item. Use [`zip()`](#zip)<br/>
+<a name='notes-77'></a><sup>77</sup> Always empty thus no items to filter.<br/>
+<a name='notes-78'></a><sup>78</sup> Needs backpressure thus not supported outside `Flowable`.<br/>
+<a name='notes-79'></a><sup>79</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.<br/>
+<a name='notes-80'></a><sup>80</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.<br/>
+<a name='notes-81'></a><sup>81</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.<br/>
+<a name='notes-82'></a><sup>82</sup> At most one item. Use [`just()`](#just).<br/>
+<a name='notes-83'></a><sup>83</sup> At most one item. Use [`map()`](#map).<br/>
+<a name='notes-84'></a><sup>84</sup> Always empty thus no items to reduce.<br/>
+<a name='notes-85'></a><sup>85</sup> At most one signal type.<br/>
+<a name='notes-86'></a><sup>86</sup> At most one item. Use [`takeUntil()`](#takeUntil).<br/>
+<a name='notes-87'></a><sup>87</sup> At most one item. Use [`filter()`](#filter).<br/>
+<a name='notes-88'></a><sup>88</sup> Use [`startWith()`](#startWith) and [`fromArray()`](#fromArray) of `Flowable` or `Observable`.<br/>
+<a name='notes-89'></a><sup>89</sup> Use [`startWith()`](#startWith) and [`just()`](#just) of another reactive type.<br/>
+<a name='notes-90'></a><sup>90</sup> Use [`startWith()`](#startWith) and [`fromIterable()`](#fromArray) of `Flowable` or `Observable`.<br/>
+<a name='notes-91'></a><sup>91</sup> Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
+<a name='notes-92'></a><sup>92</sup> At most one item. Use [`flatMap()`](#flatMap).<br/>
+<a name='notes-93'></a><sup>93</sup> Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).<br/>
+<a name='notes-94'></a><sup>94</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
+<a name='notes-95'></a><sup>95</sup> Would be no-op.<br/>
+<a name='notes-96'></a><sup>96</sup> Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).<br/>
+<a name='notes-97'></a><sup>97</sup> Use [`first`](#first), [`last`](#last) or [`single`](#single).<br/>
+<a name='notes-98'></a><sup>98</sup> Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
+<a name='notes-99'></a><sup>99</sup> Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a nested source.<br/>
+<a name='notes-100'></a><sup>100</sup> Use [`map()`](#map) to transform into a nested source.<br/>
+<a name='notes-101'></a><sup>101</sup> Always empty. Use [`andThen()`](#andThen) to bring in a nested source.<br/>
+<a name='notes-102'></a><sup>102</sup> Use [`fromPublisher()`](#fromPublisher).<br/>
+<a name='notes-103'></a><sup>103</sup> Use [`merge()`](#merge).<br/>
+<a name='notes-104'></a><sup>104</sup> Use [`mergeArray()`](#mergeArray).<br/>
+<a name='notes-105'></a><sup>105</sup> Use [`mergeWith()`](#mergeWith).<br/>
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index 42ea23dd1d..1273a5b441 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -40,6 +40,10 @@ private OperatorMatrixGenerator() {
             Flowable.class, Observable.class, Maybe.class, Single.class, Completable.class
     };
 
+    static String header(String type) {
+        return "![" + type + "](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmatrix-" + type.toLowerCase() + ".png)";
+    }
+
     public static void main(String[] args) throws IOException {
         Set<String> operatorSet = new HashSet<>();
         Map<Class<?>, Set<String>> operatorMap = new HashMap<>();
@@ -64,18 +68,24 @@ public static void main(String[] args) throws IOException {
         try (PrintWriter out = new PrintWriter(Files.newBufferedWriter(Paths.get("docs", "Operator-Matrix.md"), StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING))) {
             out.print("Operator |");
             for (Class<?> clazz : CLASSES) {
-                out.print(" `");
-                out.print(clazz.getSimpleName());
-                out.print("` |");
+                out.print(" ");
+                out.print(header(clazz.getSimpleName()));
+                out.print(" |");
             }
             out.println();
             out.print("-----|");
             for (int i = 0; i < CLASSES.length; i++) {
-                out.print(":---:|");
+                out.print("---|");
             }
             out.println();
+
+            Map<String, Integer> notesMap = new HashMap<>();
+            List<String> notesList = new ArrayList<>();
+
             for (String operatorName : sortedOperators) {
-                out.print("`");
+                out.print("<a name='");
+                out.print(operatorName);
+                out.print("'></a>`");
                 out.print(operatorName);
                 out.print("`|");
                 for (Class<?> clazz : CLASSES) {
@@ -83,11 +93,376 @@ public static void main(String[] args) throws IOException {
                         out.print(PRESENT);
                     } else {
                         out.print(ABSENT);
+                        String notes = findNotes(clazz.getSimpleName(), operatorName);
+                        if (notes != null) {
+                            Integer index = notesMap.get(notes);
+                            if (index == null) {
+                                index = notesMap.size() + 1;
+                                notesMap.put(notes, index);
+                                notesList.add(notes);
+                            }
+                            out.print(" <sup title='");
+                            out.print(notes.replace("`", "").replace("[", "").replace("]", "").replaceAll("\\(#.+\\)", ""));
+                            out.print("'>([");
+                            out.print(index);
+                            out.print("](#notes-");
+                            out.print(index);
+                            out.print("))</sup>");
+                        }
                     }
                     out.print("|");
                 }
                 out.println();
             }
+
+            if (!notesList.isEmpty()) {
+                out.println();
+                out.println("#### Notes");
+
+                for (int i = 0; i < notesList.size(); i++) {
+                    out.print("<a name='notes-");
+                    out.print(i + 1);
+                    out.print("'></a><sup>");
+                    out.print(i + 1);
+                    out.print("</sup> ");
+                    out.print(notesList.get(i));
+                    out.println("<br/>");
+                }
+            }
+        }
+    }
+
+    static String findNotes(String clazzName, String operatorName) {
+        Map<String, String> classNotes = NOTES_MAP.get(operatorName);
+        if (classNotes != null) {
+            return classNotes.get(clazzName.substring(0, 1));
+        }
+        switch (operatorName) {
+            case "empty": {
+                if ("Completable".equals(clazzName)) {
+                    return "Use [`complete()`](#complete).";
+                }
+                if ("Single".equals(clazzName)) {
+                    return "Never empty.";
+                }
+                break;
+            }
+        }
+        return null;
+    }
+
+    static final String[] NOTES = {
+            // Format
+            // FOMSC methodName note
+            "  MS  all                                  Use [`contains()`](#contains).",
+            "    C all                                  Always empty.",
+            "FOMS  andThen                              Use [`concatWith`](#concatWith).",
+            "  MS  any                                  Use [`contains()`](#contains).",
+            "    C any                                  Always empty.",
+            "FO    blockingAwait                        Use [`blockingFirst()`](#blockingFirst), [`blockingSingle()`](#blockingSingle) or [`blockingLast()`](#blockingLast).",
+            "  MS  blockingAwait                        Use [`blockingGet()`](#blockingGet).",
+            "  MS  blockingFirst                        At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingFirst                        No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MSC blockingForEach                      Use [`blockingSubscribe()`](#blockingSubscribe)",
+            "FO    blockingGet                          Use [`blockingFirst()`](#blockingFirst), [`blockingSingle()`](#blockingSingle) or [`blockingLast()`](#blockingLast).",
+            "    C blockingGet                          No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingIterable                     At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingIterable                     No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingLast                         At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingLast                         No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingLatest                       At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingLatest                       No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingMostRecent                   At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingMostRecent                   No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingNext                         At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingNext                         No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingSingle                       At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingSingle                       No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  MS  blockingStream                       At most one element to get. Use [`blockingGet()`](#blockingGet).",
+            "    C blockingStream                       No elements to get. Use [`blockingAwait()`](#blockingAwait).",
+            "  M   buffer                               Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  buffer                               Use [`map()`](#map) to transform into a list/collection.",
+            "    C buffer                               Always empty. Use [`andThen()`](#andThen) to bring in a list/collection.",
+            "  MSC cacheWithInitialCapacity             At most one element to store. Use [`cache()`](#cache).",
+            "    C cast                                 Always empty.",
+            "  M   collect                              At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  collect                              One element to collect. Use [`map()`](#map) to transform into a list/collection.",
+            "    C collect                              Always empty. Use [`andThen()`](#andThen) to bring in a collection.",
+            "  M   collectInto                          At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  collectInto                          One element to collect. Use [`map()`](#map) to transform into a list/collection.",
+            "    C collectInto                          Always empty. Use [`andThen()`](#andThen) to bring in a collection.",
+            "  MS  combineLatest                        At most one element per source. Use [`zip()`](#zip).",
+            "    C combineLatest                        Always empty. Use [`merge()`](#merge).",
+            "  MS  combineLatestArray                   At most one element per source. Use [`zipArray()`](#zipArray).",
+            "    C combineLatestArray                   Always empty. Use [`mergeArray()`](#mergeArray).",
+            "  MS  combineLatestDelayError              At most one element per source. Use [`zip()`](#zip).",
+            "    C combineLatestDelayError              Always empty. Use [`mergeDelayError()`](#mergeDelayError).",
+            "  MS  combineLatestArrayDelayError         At most one element per source. Use [`zipArray()`](#zipArray).",
+            "    C combineLatestArrayDelayError         Always empty. Use [`mergeArrayDelayError()`](#mergeArrayDelayError).",
+            "FOM   complete                             Use [`empty()`](#empty).",
+            "   S  complete                             Never empty.",
+            "    C concatArrayEager                     No items to keep ordered. Use [`mergeArray()`](#mergeArray).",
+            "    C concatArrayEagerDelayError           No items to keep ordered. Use [`mergeArrayDelayError()`](#mergeArrayDelayError).",
+            "    C concatEager                          No items to keep ordered. Use [`merge()`](#merge).",
+            "    C concatEagerDelayError                No items to keep ordered. Use [`mergeDelayError()`](#mergeDelayError).",
+            "    C concatMap                            Always empty thus no items to map.",
+            "    C concatMapCompletable                 Always empty thus no items to map.",
+            "    C concatMapCompletableDelayError       Always empty thus no items to map.",
+            "    C concatMapIterable                    Always empty thus no items to map.",
+            "    C concatMapMaybe                       Always empty thus no items to map.",
+            "    C concatMapMaybeDelayError             Always empty thus no items to map.",
+            "    C concatMapSingle                      Always empty thus no items to map.",
+            "    C concatMapSingleDelayError            Always empty thus no items to map.",
+            "    C concatMapStream                      Always empty thus no items to map.",
+            "  MS  concatMapIterable                    At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).",
+            "  MS  concatMapStream                      At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).",
+            "    C contains                             Always empty.",
+            "   S  count                                Never empty thus always 1.",
+            "    C count                                Always empty thus always 0.",
+            "  MS  debounce                             At most one item signaled so no subsequent items to work with.",
+            "    C debounce                             Always empty thus no items to work with.",
+            "   S  defaultIfEmpty                       Never empty.",
+            "    C defaultIfEmpty                       Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.",
+            "    C dematerialize                        Always empty thus no items to work with.",
+            "  MS  distinct                             At most one item, always distinct.",
+            "    C distinct                             Always empty thus no items to work with.",
+            "  MS  distinctUntilChanged                 At most one item, always distinct.",
+            "    C distinctUntilChanged                 Always empty thus no items to work with.",
+            "  MS  doAfterNext                          Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).",
+            "    C doAfterNext                          Always empty.",
+            "FO    doAfterSuccess                       Different terminology. Use [`doAfterNext()`](#doAfterNext).",
+            "    C doAfterSuccess                       Always empty thus no items to work with.",
+            " OMSC doOnCancel                           Different terminology. Use [`doOnDispose()`](#doOnDispose).",
+            "   S  doOnComplete                         Always succeeds or fails, there is no `onComplete` signal.",
+            "F     doOnDispose                          Different terminology. Use [`doOnCancel()`](#doOnCancel).",
+            "  MS  doOnEach                             At most one item. Use [`doOnEvent()`](#doOnEvent).",
+            "    C doOnEach                             Always empty thus no items to work with.",
+            "FO    doOnEvent                            Use [`doOnEach()`](#doOnEach).",
+            "  MS  doOnNext                             Different terminology. Use [`doOnSuccess()`](#doOnSuccess).",
+            "    C doOnNext                             Always empty thus no items to work with.",
+            " OMSC doOnRequest                          Backpressure related and not supported outside `Flowable`.",
+            "FO    doOnSuccess                          Different terminology. Use [`doOnNext()`](#doOnNext).",
+            "    C doOnSuccess                          Always empty thus no items to work with.",
+            "  M   elementAt                            At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).",
+            "   S  elementAt                            Always one item with index 0.",
+            "    C elementAt                            Always empty thus no items to work with.",
+            "  M   elementAtOrError                     At most one item with index 0. Use [`toSingle`](#toSingle).",
+            "   S  empty                                Never empty.",
+            "    C empty                                Use [`complete()`](#complete).",
+            "    C filter                               Always empty thus no items to work with.",
+            "  M   first                                At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).",
+            "   S  first                                Always one item.",
+            "    C first                                Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.",
+            "  M   firstElement                         At most one item, would be no-op.",
+            "   S  firstElement                         Always one item, would be no-op.",
+            "    C firstElement                         Always empty.",
+            "  M   firstOrError                         At most one item, would be no-op.",
+            "   S  firstOrError                         Always one item, would be no-op.",
+            "    C firstOrError                         Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).",
+            "  MS  firstOrErrorStage                    At most one item. Use [`toCompletionStage()`](#toCompletionStage).",
+            "    C firstOrErrorStage                    Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).",
+            "  MSC firstStage                           At most one item. Use [`toCompletionStage()`](#toCompletionStage).",
+            "    C flatMap                              Always empty thus no items to map.",
+            "    C flatMapCompletable                   Always empty thus no items to map.",
+            "    C flatMapCompletableDelayError         Always empty thus no items to map.",
+            "    C flatMapIterable                      Always empty thus no items to map.",
+            "    C flatMapMaybe                         Always empty thus no items to map.",
+            "    C flatMapMaybeDelayError               Always empty thus no items to map.",
+            "    C flatMapSingle                        Always empty thus no items to map.",
+            "    C flatMapSingleDelayError              Always empty thus no items to map.",
+            "    C flatMapStream                        Always empty thus no items to map.",
+            "  MS  flatMapIterable                      At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).",
+            "  MS  flatMapStream                        At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).",
+            "F     flatMapObservable                    Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).",
+            " O    flatMapObservable                    Use [`flatMap`](#flatMap).",
+            "    C flatMapObservable                    Always empty thus no items to map.",
+            " O    flatMapPublisher                     Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).",
+            "F     flatMapPublisher                     Use [`flatMap`](#flatMap).",
+            "    C flatMapPublisher                     Always empty thus no items to map.",
+            "FO    flatMapSingleElement                 Use [`flatMapSingle`](#flatMapSingle).",
+            "   S  flatMapSingleElement                 Use [`flatMap`](#flatMap).",
+            "    C flatMapSingleElement                 Always empty thus no items to map.",
+            "FO    flattenAsFlowable                    Use [`flatMapIterable()`](#flatMapIterable).",
+            "    C flattenAsFlowable                    Always empty thus no items to map.",
+            "FO    flattenAsObservable                  Use [`flatMapIterable()`](#flatMapIterable).",
+            "    C flattenAsObservable                  Always empty thus no items to map.",
+            "FO    flattenStreamAsFlowable              Use [`flatMapStream()`](#flatMapStream).",
+            "    C flattenStreamAsFlowable              Always empty thus no items to map.",
+            "FO    flattenStreamAsObservable            Use [`flatMapStream()`](#flatMapStream).",
+            "    C flattenStreamAsObservable            Always empty thus no items to map.",
+            "  MSC forEach                              Use [`subscribe()`](#subscribe).",
+            "  MSC forEachWhile                         Use [`subscribe()`](#subscribe).",
+            "  M   fromArray                            At most one item. Use [`just()`](#just) or [`empty()`](#empty).",
+            "   S  fromArray                            Always one item. Use [`just()`](#just).",
+            "    C fromArray                            Always empty. Use [`complete()`](#complete).",
+            "   S  fromCompletable                      Always error.",
+            "    C fromCompletable                      Use [`wrap()`](#wrap).",
+            "  M   fromIterable                         At most one item. Use [`just()`](#just) or [`empty()`](#empty).",
+            "   S  fromIterable                         Always one item. Use [`just()`](#just).",
+            "    C fromIterable                         Always empty. Use [`complete()`](#complete).",
+            "  M   fromMaybe                            Use [`wrap()`](#wrap).",
+            " O    fromObservable                       Use [`wrap()`](#wrap).",
+            "   S  fromOptional                         Always one item. Use [`just()`](#just).",
+            "    C fromOptional                         Always empty. Use [`complete()`](#complete).",
+            "  M   fromStream                           At most one item. Use [`just()`](#just) or [`empty()`](#empty).",
+            "   S  fromStream                           Always one item. Use [`just()`](#just).",
+            "    C fromStream                           Always empty. Use [`complete()`](#complete).",
+            "  MSC generate                             Use [`fromSupplier()`](#fromSupplier).",
+            "  MS  groupBy                              At most one item.",
+            "    C groupBy                              Always empty thus no items to group.",
+            "  MS  groupJoin                            At most one item.",
+            "    C groupJoin                            Always empty thus no items to join.",
+            "FO    ignoreElement                        Use [`ignoreElements()`](#ignoreElements).",
+            "    C ignoreElement                        Always empty.",
+            "  MS  ignoreElements                       Use [`ignoreElement()`](#ignoreElement).",
+            "    C ignoreElements                       Always empty.",
+            "  MSC interval                             At most one item. Use [`timer()`](#timer).",
+            "  MSC intervalRange                        At most one item. Use [`timer()`](#timer).",
+            "   S  isEmpty                              Always one item.",
+            "    C isEmpty                              Always empty.",
+            "  MS  join                                 At most one item. Use [`zip()`](#zip)",
+            "    C join                                 Always empty thus no items to join.",
+            "  M   last                                 At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).",
+            "   S  last                                 Always one item.",
+            "    C last                                 Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.",
+            "  M   lastElement                          At most one item, would be no-op.",
+            "   S  lastElement                          Always one item, would be no-op.",
+            "    C lastElement                          Always empty.",
+            "  M   lastOrError                          At most one item, would be no-op.",
+            "   S  lastOrError                          Always one item, would be no-op.",
+            "    C lastOrError                          Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).",
+            "  MS  lastOrErrorStage                     At most one item. Use [`toCompletionStage()`](#toCompletionStage).",
+            "    C lastOrErrorStage                     Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).",
+            "  MSC lastStage                            At most one item. Use [`toCompletionStage()`](#toCompletionStage).",
+            "    C map                                  Always empty thus no items to map.",
+            "    C mapOptional                          Always empty thus no items to map.",
+            "    C ofType                               Always empty thus no items to filter.",
+            " OMSC onBackpressureBuffer                 Backpressure related and not supported outside `Flowable`.",
+            " OMSC onBackpressureDrop                   Backpressure related and not supported outside `Flowable`.",
+            " OMSC onBackpressureLatest                 Backpressure related and not supported outside `Flowable`.",
+            " OMSC parallel                             Needs backpressure thus not supported outside `Flowable`.",
+            "  M   publish                              Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.",
+            "   S  publish                              Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.",
+            "    C publish                              Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.",
+            "  MS  range                                At most one item. Use [`just()`](#just).",
+            "    C range                                Always empty. Use [`complete()`](#complete).",
+            "  MS  rangeLong                            At most one item. Use [`just()`](#just).",
+            "    C rangeLong                            Always empty. Use [`complete()`](#complete).",
+            " OMSC rebatchRequests                      Backpressure related and not supported outside `Flowable`.",
+            "  MS  reduce                               At most one item. Use [`map()`](#map).",
+            "    C reduce                               Always empty thus no items to reduce.",
+            "  MS  reduceWith                           At most one item. Use [`map()`](#map).",
+            "    C reduceWith                           Always empty thus no items to reduce.",
+            "  M   replay                               Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.",
+            "   S  replay                               Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.",
+            "    C replay                               Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.",
+            "  MS  sample                               At most one item, would be no-op.",
+            "    C sample                               Always empty thus no items to work with.",
+            "  MS  scan                                 At most one item. Use [`map()`](#map).",
+            "    C scan                                 Always empty thus no items to reduce.",
+            "  MS  scanWith                             At most one item. Use [`map()`](#map).",
+            "    C scanWith                             Always empty thus no items to reduce.",
+            "  MSC serialize                            At most one signal type.",
+            "  M   share                                Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.",
+            "   S  share                                Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.",
+            "    C share                                Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.",
+            "  M   single                               At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).",
+            "   S  single                               Always one item.",
+            "    C single                               Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.",
+            "  M   singleElement                        At most one item, would be no-op.",
+            "   S  singleElement                        Always one item, would be no-op.",
+            "    C singleElement                        Always empty.",
+            "  M   singleOrError                        At most one item, would be no-op.",
+            "   S  singleOrError                        Always one item, would be no-op.",
+            "    C singleOrError                        Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).",
+            "  MS  singleOrErrorStage                   At most one item. Use [`toCompletionStage()`](#toCompletionStage).",
+            "    C singleOrErrorStage                   Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).",
+            "  MSC singleStage                          At most one item. Use [`toCompletionStage()`](#toCompletionStage).",
+            "  MSC skip                                 At most one item, would be no-op.",
+            "  MSC skipLast                             At most one item, would be no-op.",
+            "  MS  skipWhile                            At most one item. Use [`filter()`](#filter).",
+            "    C skipWhile                            Always empty.",
+            "  MSC skipUntil                            At most one item. Use [`takeUntil()`](#takeUntil).",
+            "  MSC sorted                               At most one item.",
+            "  MSC startWithArray                       Use [`startWith()`](#startWith) and [`fromArray()`](#fromArray) of `Flowable` or `Observable`.",
+            "  MSC startWithItem                        Use [`startWith()`](#startWith) and [`just()`](#just) of another reactive type.",
+            "  MSC startWithIterable                    Use [`startWith()`](#startWith) and [`fromIterable()`](#fromArray) of `Flowable` or `Observable`.",
+            "   S  switchIfEmpty                        Never empty.",
+            "    C switchIfEmpty                        Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).",
+            "  MS  switchMap                            At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMap                            Always empty thus no items to map.",
+            "  MS  switchMapDelayError                  At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapDelayError                  Always empty thus no items to map.",
+            "  MS  switchMapCompletable                 At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapCompletable                 Always empty thus no items to map.",
+            "  MS  switchMapCompletableDelayError       At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapCompletableDelayError       Always empty thus no items to map.",
+            "  MS  switchMapMaybe                       At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapMaybe                       Always empty thus no items to map.",
+            "  MS  switchMapMaybeDelayError             At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapMaybeDelayError             Always empty thus no items to map.",
+            "  MS  switchMapSingle                      At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapSingle                      Always empty thus no items to map.",
+            "  MS  switchMapSingleDelayError            At most one item. Use [`flatMap()`](#flatMap).",
+            "    C switchMapSingleDelayError            Always empty thus no items to map.",
+            "  MSC take                                 At most one item, would be no-op.",
+            "  MSC takeLast                             At most one item, would be no-op.",
+            "  MS  takeWhile                            At most one item. Use [`filter()`](#filter).",
+            "    C takeWhile                            Always empty.",
+            "  MS  throttleFirst                        At most one item signaled so no subsequent items to work with.",
+            "    C throttleFirst                        Always empty thus no items to work with.",
+            "  MS  throttleLast                         At most one item signaled so no subsequent items to work with.",
+            "    C throttleLast                         Always empty thus no items to work with.",
+            "  MS  throttleLatest                       At most one item signaled so no subsequent items to work with.",
+            "    C throttleLatest                       Always empty thus no items to work with.",
+            "  MS  throttleWithTimeout                  At most one item signaled so no subsequent items to work with.",
+            "    C throttleWithTimeout                  Always empty thus no items to work with.",
+            "    C timestamp                            Always empty thus no items to work with.",
+            "FO    toCompletionStage                    Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).",
+            "  M   toList                               At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  toList                               One element to collect. Use [`map()`](#map) to transform into a list/collection.",
+            "    C toList                               Always empty. Use [`andThen()`](#andThen) to bring in a collection.",
+            "  M   toMap                                At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  toMap                                One element to collect. Use [`map()`](#map) to transform into a list/collection.",
+            "    C toMap                                Always empty. Use [`andThen()`](#andThen) to bring in a collection.",
+            "  M   toMultimap                           At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  toMultimap                           One element to collect. Use [`map()`](#map) to transform into a list/collection.",
+            "    C toMultimap                           Always empty. Use [`andThen()`](#andThen) to bring in a collection.",
+            "FO    toMaybe                              Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).",
+            "  M   toMaybe                              Would be no-op.",
+            " O    toObservable                         Would be no-op.",
+            "FO    toSingle                             Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).",
+            "   S  toSingle                             Would be no-op.",
+            "FO    toSingleDefault                      Use [`first`](#first), [`last`](#last) or [`single`](#single).",
+            "  M   toSingleDefault                      Use [`defaultIfEmpty()`](#defaultIfEmpty).",
+            "   S  toSingleDefault                      Would be no-op.",
+            "  M   toSortedList                         At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
+            "   S  toSortedList                         One element to collect. Use [`map()`](#map) to transform into a list/collection.",
+            "    C toSortedList                         Always empty. Use [`andThen()`](#andThen) to bring in a collection.",
+            "  M   window                               Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a nested source.",
+            "   S  window                               Use [`map()`](#map) to transform into a nested source.",
+            "    C window                               Always empty. Use [`andThen()`](#andThen) to bring in a nested source.",
+            "  MS  withLatestFrom                       At most one element per source. Use [`zip()`](#zip).",
+            "    C withLatestFrom                       Always empty. Use [`merge()`](#merge).",
+            "F     wrap                                 Use [`fromPublisher()`](#fromPublisher).",
+            "    C zip                                  Use [`merge()`](#merge).",
+            "    C zipArray                             Use [`mergeArray()`](#mergeArray).",
+            "    C zipWith                              Use [`mergeWith()`](#mergeWith).",
+    };
+
+    static final Map<String, Map<String, String>> NOTES_MAP;
+    static {
+        NOTES_MAP = new HashMap<>();
+        for (String s : NOTES) {
+            char[] classes = s.substring(0, 5).trim().toCharArray();
+            int idx = s.indexOf(' ', 7);
+            String method = s.substring(6, idx);
+            String note = s.substring(idx).trim();
+
+            for (char c : classes) {
+                NOTES_MAP.computeIfAbsent(method, v -> new HashMap<>())
+                .put(String.valueOf(c), note);
+            }
         }
     }
 }

From e8d59c52c5c5391a668f33c6128f27766d8d79b3 Mon Sep 17 00:00:00 2001
From: akarnokd <akarnokd@gmail.com>
Date: Wed, 22 Jan 2020 14:22:11 +0100
Subject: [PATCH 05/37] Minor fix to the operator matrix.

---
 docs/Operator-Matrix.md                         | 17 ++++++++---------
 .../internal/util/OperatorMatrixGenerator.java  |  1 +
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 832d64311d..3c3ef2c765 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -80,7 +80,6 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
 <a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
 <a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([49](#notes-49))</sup>|
-<a name='equals'></a>`equals`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
 <a name='error'></a>`error`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
 <a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
@@ -173,7 +172,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
 <a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
 <a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
-<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
 <a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|
 <a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
 <a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
@@ -219,15 +218,15 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
 <a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([93](#notes-93))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
 <a name='toList'></a>`toList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='toMap'></a>`toMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
-<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toMultimap'></a>`toMultimap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
-<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([95](#notes-95))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toSortedList'></a>`toSortedList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='unsafeCreate'></a>`unsafeCreate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='unsubscribeOn'></a>`unsubscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -333,8 +332,8 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='notes-91'></a><sup>91</sup> Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
 <a name='notes-92'></a><sup>92</sup> At most one item. Use [`flatMap()`](#flatMap).<br/>
 <a name='notes-93'></a><sup>93</sup> Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).<br/>
-<a name='notes-94'></a><sup>94</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
-<a name='notes-95'></a><sup>95</sup> Would be no-op.<br/>
+<a name='notes-94'></a><sup>94</sup> Would be no-op.<br/>
+<a name='notes-95'></a><sup>95</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
 <a name='notes-96'></a><sup>96</sup> Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).<br/>
 <a name='notes-97'></a><sup>97</sup> Use [`first`](#first), [`last`](#last) or [`single`](#single).<br/>
 <a name='notes-98'></a><sup>98</sup> Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index 1273a5b441..970d6e36bb 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -419,6 +419,7 @@ static String findNotes(String clazzName, String operatorName) {
             "    C throttleWithTimeout                  Always empty thus no items to work with.",
             "    C timestamp                            Always empty thus no items to work with.",
             "FO    toCompletionStage                    Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).",
+            "F     toFlowable                           Would be no-op.",
             "  M   toList                               At most one element to collect. Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a list/collection.",
             "   S  toList                               One element to collect. Use [`map()`](#map) to transform into a list/collection.",
             "    C toList                               Always empty. Use [`andThen()`](#andThen) to bring in a collection.",

From 5dbc2a84f970bf0bb8670bec13ab2aa836ebad66 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Wed, 22 Jan 2020 17:37:14 +0100
Subject: [PATCH 06/37] 3.x: Add last missing throws tag to JavaDocs (#6860)

---
 .../io/reactivex/rxjava3/core/Flowable.java   |  7 +-
 .../io/reactivex/rxjava3/core/Single.java     |  1 +
 .../internal/util/JavadocNoThrows.java        | 72 +++++++++++++++++++
 .../validators/ParamValidationNaming.java     |  3 +
 4 files changed, 80 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/util/JavadocNoThrows.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 5f5aff68c6..0106f42ce9 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -213,7 +213,7 @@ public static <T> Flowable<T> amb(@NonNull Iterable<@NonNull ? extends Publisher
     @BackpressureSupport(BackpressureKind.PASS_THROUGH)
     @SchedulerSupport(SchedulerSupport.NONE)
     @SafeVarargs
-    public static <T> Flowable<T> ambArray(Publisher<@NonNull ? extends T>... sources) {
+    public static <T> Flowable<T> ambArray(@NonNull Publisher<@NonNull ? extends T>... sources) {
         Objects.requireNonNull(sources, "sources is null");
         int len = sources.length;
         if (len == 0) {
@@ -1915,7 +1915,7 @@ public static <T> Flowable<T> empty() {
      * @param supplier
      *            a {@link Supplier} factory to return a {@link Throwable} for each individual {@code Subscriber}
      * @param <T>
-     *            the type of the items (ostensibly) emitted by the {@link Publisher}
+     *            the type of the items (ostensibly) emitted by the resulting {@code Flowable}
      * @return the new {@code Flowable} instance
      * @throws NullPointerException if {@code supplier} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
@@ -1944,7 +1944,7 @@ public static <T> Flowable<T> error(@NonNull Supplier<? extends Throwable> suppl
      * @param throwable
      *            the particular {@link Throwable} to pass to {@link Subscriber#onError onError}
      * @param <T>
-     *            the type of the items (ostensibly) emitted by the {@link Publisher}
+     *            the type of the items (ostensibly) emitted by the resulting {@code Flowable}
      * @return the new {@code Flowable} instance
      * @throws NullPointerException if {@code throwable} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
@@ -8760,6 +8760,7 @@ public final Flowable<T> delay(long time, @NonNull TimeUnit unit, @NonNull Sched
      *            then used to delay the emission of that item by the resulting {@code Flowable} until the {@code Publisher}
      *            returned from {@code itemDelay} emits an item
      * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code subscriptionIndicator} and {@code itemDelayIndicator} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
      */
     @CheckReturnValue
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index f915bdc5b2..c93bfa9282 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -681,6 +681,7 @@ public static <T> Single<T> error(@NonNull Throwable throwable) {
      *            the type of object that the {@code Future} returns, and also the type of item to be emitted by
      *            the resulting {@code Single}
      * @return the new {@code Single} that emits the item from the source {@code Future}
+     * @throws NullPointerException if {@code future} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/from.html">ReactiveX operators documentation: From</a>
      * @see #fromFuture(Future, long, TimeUnit)
      * @see #fromCompletionStage(CompletionStage)
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/JavadocNoThrows.java b/src/test/java/io/reactivex/rxjava3/internal/util/JavadocNoThrows.java
new file mode 100644
index 0000000000..985ac202c3
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/JavadocNoThrows.java
@@ -0,0 +1,72 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+package io.reactivex.rxjava3.internal.util;
+
+import java.io.File;
+import java.nio.file.Files;
+import java.util.List;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.parallel.ParallelFlowable;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+/**
+ * Scan the JavaDocs of the base classes and list those which do not have the {@code @throws} tag.
+ * The lack is not an error by itself but worth looking at.
+ */
+public final class JavadocNoThrows {
+
+    private JavadocNoThrows() {
+        throw new IllegalArgumentException("No instances!");
+    }
+
+    public static void main(String[] args) throws Exception {
+        for (Class<?> clazz : CLASSES) {
+            String clazzName = clazz.getSimpleName();
+            String packageName = clazz.getPackage().getName();
+            File f = TestHelper.findSource(clazzName, packageName);
+
+            List<String> lines = Files.readAllLines(f.toPath());
+
+            for (int i = 1; i < lines.size(); i++) {
+                String line = lines.get(i).trim();
+
+                if (line.startsWith("/**")) {
+                    boolean found = false;
+                    for (int j = i + 1; j < lines.size(); j++) {
+
+                        String line2 = lines.get(j).trim();
+                        if (line2.startsWith("public")) {
+                            if (line2.endsWith("() {")) {
+                                found = true;
+                            }
+                            break;
+                        }
+                        if (line2.startsWith("* @throws")) {
+                            found = true;
+                            break;
+                        }
+                    }
+
+                    if (!found) {
+                        System.out.printf(" at %s.%s.method(%s.java:%s)%n%n", packageName, clazzName, clazzName, i + 1);
+                    }
+                }
+            }
+        }
+    }
+
+    static final Class<?>[] CLASSES = {
+            Flowable.class, Observable.class, Maybe.class, Single.class, Completable.class, ParallelFlowable.class
+    };
+}
diff --git a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
index ba307d394d..2ce716e342 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
@@ -523,6 +523,9 @@ static final class ValidatorStrings {
             new ValidatorStrings("stage", "* @throws NullPointerException"),
             new ValidatorStrings("stream", "* @throws NullPointerException"),
             new ValidatorStrings("collector", "* @throws NullPointerException"),
+            new ValidatorStrings("subscriptionIndicator", "* @throws NullPointerException"),
+            new ValidatorStrings("itemDelayIndicator", "* @throws NullPointerException"),
+            new ValidatorStrings("future", "* @throws NullPointerException"),
 
             new ValidatorStrings("parallelism", "* @throws IllegalArgumentException"),
             new ValidatorStrings("prefetch", "* @throws IllegalArgumentException"),

From 49f1a6d0f0540d6b98e2c11d70ad54ff0c4bc18f Mon Sep 17 00:00:00 2001
From: "dependabot-preview[bot]"
 <27856297+dependabot-preview[bot]@users.noreply.github.com>
Date: Thu, 23 Jan 2020 09:50:48 +0100
Subject: [PATCH 07/37] Bump biz.aQute.bnd.gradle from 4.3.1 to 5.0.0 (#6861)

Bumps [biz.aQute.bnd.gradle](https://github.com/bndtools/bnd) from 4.3.1 to 5.0.0.
- [Release notes](https://github.com/bndtools/bnd/releases)
- [Changelog](https://github.com/bndtools/bnd/blob/master/docs/ADDING_RELEASE_DOCS.md)
- [Commits](https://github.com/bndtools/bnd/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
---
 build.gradle | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build.gradle b/build.gradle
index ce041a954f..b0a12f1c79 100644
--- a/build.gradle
+++ b/build.gradle
@@ -15,7 +15,7 @@ buildscript {
   ext.licenseVersion = "0.15.0"
   ext.bintrayVersion = "1.8.4"
   ext.jfrogExtractorVersion = "4.13.0"
-  ext.bndVersion = "4.3.1"
+  ext.bndVersion = "5.0.0"
   ext.checkstyleVersion = "8.26"
 
   // --------------------------------------

From bb3260ec3729d9d9c0934a958f3added8ca65408 Mon Sep 17 00:00:00 2001
From: Paul Estrada <2215585+pestrada@users.noreply.github.com>
Date: Fri, 24 Jan 2020 01:41:40 -0600
Subject: [PATCH 08/37] add delayError to Maybe.delay (#6864)

---
 .../java/io/reactivex/rxjava3/core/Maybe.java | 65 +++++++++++++++++--
 .../internal/operators/maybe/MaybeDelay.java  | 20 ++++--
 .../operators/maybe/MaybeDelayTest.java       | 28 ++++++++
 .../ParamValidationCheckerTest.java           |  2 +
 4 files changed, 102 insertions(+), 13 deletions(-)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 4322afaa93..6260f3e206 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -2672,6 +2672,7 @@ public final Single<T> defaultIfEmpty(@NonNull T defaultItem) {
     /**
      * Returns a {@code Maybe} that signals the events emitted by the current {@code Maybe} shifted forward in time by a
      * specified delay.
+     * An error signal will not be delayed.
      * <p>
      * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
      * <dl>
@@ -2682,17 +2683,68 @@ public final Single<T> defaultIfEmpty(@NonNull T defaultItem) {
      * @param time
      *            the delay to shift the source by
      * @param unit
-     *            the {@link TimeUnit} in which {@code period} is defined
+     *            the {@link TimeUnit} in which {@code time} is defined
      * @return the new {@code Maybe} instance
      * @throws NullPointerException if {@code unit} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
-     * @see #delay(long, TimeUnit, Scheduler)
+     * @see #delay(long, TimeUnit, Scheduler, boolean)
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
     @NonNull
     public final Maybe<T> delay(long time, @NonNull TimeUnit unit) {
-        return delay(time, unit, Schedulers.computation());
+        return delay(time, unit, Schedulers.computation(), false);
+    }
+
+    /**
+     * Returns a {@code Maybe} that signals the events emitted by the current {@code Maybe} shifted forward in time by a
+     * specified delay.
+     * <p>
+     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
+     * <dl>
+     *   <dt><b>Scheduler:</b></dt>
+     *   <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param time the delay to shift the source by
+     * @param unit the {@link TimeUnit} in which {@code time} is defined
+     * @param delayError if {@code true}, both success and error signals are delayed. if {@code false}, only success signals are delayed.
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code unit} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
+     * @see #delay(long, TimeUnit, Scheduler, boolean)
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    @NonNull
+    public final Maybe<T> delay(long time, @NonNull TimeUnit unit, boolean delayError) {
+        return delay(time, unit, Schedulers.computation(), delayError);
+    }
+
+    /**
+     * Returns a {@code Maybe} that signals the events emitted by the current {@code Maybe} shifted forward in time by a
+     * specified delay.
+     * An error signal will not be delayed.
+     * <p>
+     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
+     * <dl>
+     *   <dt><b>Scheduler:</b></dt>
+     *   <dd>you specify the {@link Scheduler} where the non-blocking wait and emission happens</dd>
+     * </dl>
+     *
+     * @param time the delay to shift the source by
+     * @param unit the {@link TimeUnit} in which {@code time} is defined
+     * @param scheduler the {@code Scheduler} to use for delaying
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
+     * @see #delay(long, TimeUnit, Scheduler, boolean)
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    @NonNull
+    public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        return delay(time, unit, scheduler, false);
     }
 
     /**
@@ -2708,9 +2760,10 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit) {
      * @param time
      *            the delay to shift the source by
      * @param unit
-     *            the time unit of {@code delay}
+     *            the {@link TimeUnit} in which {@code time} is defined
      * @param scheduler
      *            the {@code Scheduler} to use for delaying
+     * @param delayError if {@code true}, both success and error signals are delayed. if {@code false}, only success signals are delayed.
      * @return the new {@code Maybe} instance
      * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
@@ -2718,10 +2771,10 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit) {
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.CUSTOM)
-    public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+    public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) {
         Objects.requireNonNull(unit, "unit is null");
         Objects.requireNonNull(scheduler, "scheduler is null");
-        return RxJavaPlugins.onAssembly(new MaybeDelay<>(this, Math.max(0L, time), unit, scheduler));
+        return RxJavaPlugins.onAssembly(new MaybeDelay<>(this, Math.max(0L, time), unit, scheduler, delayError));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelay.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelay.java
index 6885763cbd..3e6922a339 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelay.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelay.java
@@ -33,16 +33,19 @@ public final class MaybeDelay<T> extends AbstractMaybeWithUpstream<T, T> {
 
     final Scheduler scheduler;
 
-    public MaybeDelay(MaybeSource<T> source, long delay, TimeUnit unit, Scheduler scheduler) {
+    final boolean delayError;
+
+    public MaybeDelay(MaybeSource<T> source, long delay, TimeUnit unit, Scheduler scheduler, boolean delayError) {
         super(source);
         this.delay = delay;
         this.unit = unit;
         this.scheduler = scheduler;
+        this.delayError = delayError;
     }
 
     @Override
     protected void subscribeActual(MaybeObserver<? super T> observer) {
-        source.subscribe(new DelayMaybeObserver<>(observer, delay, unit, scheduler));
+        source.subscribe(new DelayMaybeObserver<>(observer, delay, unit, scheduler, delayError));
     }
 
     static final class DelayMaybeObserver<T>
@@ -59,15 +62,18 @@ static final class DelayMaybeObserver<T>
 
         final Scheduler scheduler;
 
+        final boolean delayError;
+
         T value;
 
         Throwable error;
 
-        DelayMaybeObserver(MaybeObserver<? super T> actual, long delay, TimeUnit unit, Scheduler scheduler) {
+        DelayMaybeObserver(MaybeObserver<? super T> actual, long delay, TimeUnit unit, Scheduler scheduler, boolean delayError) {
             this.downstream = actual;
             this.delay = delay;
             this.unit = unit;
             this.scheduler = scheduler;
+            this.delayError = delayError;
         }
 
         @Override
@@ -105,21 +111,21 @@ public void onSubscribe(Disposable d) {
         @Override
         public void onSuccess(T value) {
             this.value = value;
-            schedule();
+            schedule(delay);
         }
 
         @Override
         public void onError(Throwable e) {
             this.error = e;
-            schedule();
+            schedule(delayError ? delay : 0);
         }
 
         @Override
         public void onComplete() {
-            schedule();
+            schedule(delay);
         }
 
-        void schedule() {
+        void schedule(long delay) {
             DisposableHelper.replace(this, scheduler.scheduleDirect(this, delay, unit));
         }
     }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelayTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelayTest.java
index 747b96faf1..14448c3f2c 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelayTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDelayTest.java
@@ -96,4 +96,32 @@ public Maybe<Object> apply(Maybe<Object> f) throws Exception {
             }
         });
     }
+
+    @Test
+    public void delayedErrorOnSuccess() {
+        final TestScheduler scheduler = new TestScheduler();
+        final TestObserver<Integer> observer = Maybe.just(1)
+                .delay(5, TimeUnit.SECONDS, scheduler, true)
+                .test();
+
+        scheduler.advanceTimeTo(2, TimeUnit.SECONDS);
+        observer.assertNoValues();
+
+        scheduler.advanceTimeTo(5, TimeUnit.SECONDS);
+        observer.assertValue(1);
+    }
+
+    @Test
+    public void delayedErrorOnError() {
+        final TestScheduler scheduler = new TestScheduler();
+        final TestObserver<?> observer = Maybe.error(new TestException())
+                .delay(5, TimeUnit.SECONDS, scheduler, true)
+                .test();
+
+        scheduler.advanceTimeTo(2, TimeUnit.SECONDS);
+        observer.assertNoErrors();
+
+        scheduler.advanceTimeTo(5, TimeUnit.SECONDS);
+        observer.assertError(TestException.class);
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java
index 403a83964a..7eff55d15e 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationCheckerTest.java
@@ -289,6 +289,8 @@ public void checkParallelFlowable() {
         // negative time is considered as zero time
         addOverride(new ParamOverride(Maybe.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class));
         addOverride(new ParamOverride(Maybe.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Scheduler.class));
+        addOverride(new ParamOverride(Maybe.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Boolean.TYPE));
+        addOverride(new ParamOverride(Maybe.class, 0, ParamMode.ANY, "delay", Long.TYPE, TimeUnit.class, Scheduler.class, Boolean.TYPE));
 
         // zero repeat is allowed
         addOverride(new ParamOverride(Maybe.class, 0, ParamMode.NON_NEGATIVE, "repeat", Long.TYPE));

From 33a1dcfab98463d41d5b1502e66fa82b6d9ae3c6 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Fri, 24 Jan 2020 17:35:55 +0100
Subject: [PATCH 09/37] 3.x: Add Maybe/Single/Completable blockingSubscribe
 (#6862)

* 3.x: Add Maybe/Single/Completable blockingSubscribe

* Update marble dimensions
---
 .../reactivex/rxjava3/core/Completable.java   | 100 ++++
 .../java/io/reactivex/rxjava3/core/Maybe.java | 131 ++++-
 .../io/reactivex/rxjava3/core/Single.java     | 100 ++++
 .../BlockingDisposableMultiObserver.java      | 154 ++++++
 .../observers/BlockingMultiObserver.java      |  38 ++
 .../CompletableBlockingSubscribeTest.java     | 331 ++++++++++++
 .../maybe/MaybeBlockingSubscribeTest.java     | 502 ++++++++++++++++++
 .../single/SingleBlockingSubscribeTest.java   | 343 ++++++++++++
 8 files changed, 1698 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/observers/BlockingDisposableMultiObserver.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableBlockingSubscribeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeBlockingSubscribeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleBlockingSubscribeTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 1266255315..0913ac398d 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -1310,6 +1310,106 @@ public final boolean blockingAwait(long timeout, @NonNull TimeUnit unit) {
         return observer.blockingAwait(timeout, unit);
     }
 
+    /**
+     * Subscribes to the current {@code Completable} and <em>blocks the current thread</em> until it terminates.
+     * <p>
+     * <img width="640" height="346" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingSubscribe.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If the current {@code Completable} signals an error,
+     *  the {@link Throwable} is routed to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, an {@link InterruptedException} is routed to the same global error handler.
+     *  </dd>
+     * </dl>
+     * @since 3.0.0
+     * @see #blockingSubscribe(Action)
+     * @see #blockingSubscribe(Action, Consumer)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe() {
+        blockingSubscribe(Functions.EMPTY_ACTION, Functions.ERROR_CONSUMER);
+    }
+
+    /**
+     * Subscribes to the current {@code Completable} and calls given {@code onComplete} callback on the <em>current thread</em>
+     * when it completes normally.
+     * <p>
+     * <img width="640" height="351" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingSubscribe.a.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either the current {@code Completable} signals an error or {@code onComplete} throws,
+     *  the respective {@link Throwable} is routed to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, an {@link InterruptedException} is routed to the same global error handler.
+     *  </dd>
+     * </dl>
+     * @param onComplete the {@link Action} to call if the current {@code Completable} completes normally
+     * @throws NullPointerException if {@code onComplete} is {@code null}
+     * @since 3.0.0
+     * @see #blockingSubscribe(Action, Consumer)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Action onComplete) {
+        blockingSubscribe(onComplete, Functions.ERROR_CONSUMER);
+    }
+
+    /**
+     * Subscribes to the current {@code Completable} and calls the appropriate callback on the <em>current thread</em>
+     * when it terminates.
+     * <p>
+     * <img width="640" height="352" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingSubscribe.ac.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either {@code onComplete} or {@code onError} throw, the {@link Throwable} is routed to the
+     *  global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, the {@code onError} consumer is called with an {@link InterruptedException}.
+     *  </dd>
+     * </dl>
+     * @param onComplete the {@link Action} to call if the current {@code Completable} completes normally
+     * @param onError the {@link Consumer} to call if the current {@code Completable} signals an error
+     * @throws NullPointerException if {@code onComplete} or {@code onError} is {@code null}
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Action onComplete, @NonNull Consumer<? super Throwable> onError) {
+        Objects.requireNonNull(onComplete, "onComplete is null");
+        Objects.requireNonNull(onError, "onError is null");
+        BlockingMultiObserver<Void> observer = new BlockingMultiObserver<>();
+        subscribe(observer);
+        observer.blockingConsume(Functions.emptyConsumer(), onError, onComplete);
+    }
+
+    /**
+     * Subscribes to the current {@code Completable} and calls the appropriate {@link CompletableObserver} method on the <em>current thread</em>.
+     * <p>
+     * <img width="640" height="468" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingSubscribe.o.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>An {@code onError} signal is delivered to the {@link CompletableObserver#onError(Throwable)} method.
+     *  If any of the {@code CompletableObserver}'s methods throw, the {@link RuntimeException} is propagated to the caller of this method.
+     *  If the current thread is interrupted, an {@link InterruptedException} is delivered to {@code observer.onError}.
+     *  </dd>
+     * </dl>
+     * @param observer the {@code CompletableObserver} to call methods on the current thread
+     * @throws NullPointerException if {@code observer} is {@code null}
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull CompletableObserver observer) {
+        Objects.requireNonNull(observer, "observer is null");
+        BlockingDisposableMultiObserver<Void> blockingObserver = new BlockingDisposableMultiObserver<>();
+        observer.onSubscribe(blockingObserver);
+        subscribe(blockingObserver);
+        blockingObserver.blockingConsume(observer);
+    }
+
     /**
      * Subscribes to this {@code Completable} only once, when the first {@link CompletableObserver}
      * subscribes to the result {@code Completable}, caches its terminal event
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 6260f3e206..0d0d6f5473 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -26,7 +26,7 @@
 import io.reactivex.rxjava3.internal.functions.*;
 import io.reactivex.rxjava3.internal.fuseable.*;
 import io.reactivex.rxjava3.internal.jdk8.*;
-import io.reactivex.rxjava3.internal.observers.BlockingMultiObserver;
+import io.reactivex.rxjava3.internal.observers.*;
 import io.reactivex.rxjava3.internal.operators.flowable.*;
 import io.reactivex.rxjava3.internal.operators.maybe.*;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
@@ -2475,6 +2475,135 @@ public final T blockingGet(@NonNull T defaultValue) {
         return observer.blockingGet(defaultValue);
     }
 
+    /**
+     * Subscribes to the current {@code Maybe} and <em>blocks the current thread</em> until it terminates.
+     * <p>
+     * <img width="640" height="238" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingSubscribe.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If the current {@code Maybe} signals an error,
+     *  the {@link Throwable} is routed to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, an {@link InterruptedException} is routed to the same global error handler.
+     *  </dd>
+     * </dl>
+     * @since 3.0.0
+     * @see #blockingSubscribe(Consumer)
+     * @see #blockingSubscribe(Consumer, Consumer)
+     * @see #blockingSubscribe(Consumer, Consumer, Action)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe() {
+        blockingSubscribe(Functions.emptyConsumer(), Functions.ERROR_CONSUMER, Functions.EMPTY_ACTION);
+    }
+
+    /**
+     * Subscribes to the current {@code Maybe} and calls given {@code onSuccess} callback on the <em>current thread</em>
+     * when it completes normally.
+     * <p>
+     * <img width="640" height="245" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingSubscribe.c.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either the current {@code Maybe} signals an error or {@code onSuccess} throws,
+     *  the respective {@link Throwable} is routed to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, an {@link InterruptedException} is routed to the same global error handler.
+     *  </dd>
+     * </dl>
+     * @param onSuccess the {@link Consumer} to call if the current {@code Maybe} succeeds
+     * @throws NullPointerException if {@code onSuccess} is {@code null}
+     * @since 3.0.0
+     * @see #blockingSubscribe(Consumer, Consumer)
+     * @see #blockingSubscribe(Consumer, Consumer, Action)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess) {
+        blockingSubscribe(onSuccess, Functions.ERROR_CONSUMER, Functions.EMPTY_ACTION);
+    }
+
+    /**
+     * Subscribes to the current {@code Maybe} and calls the appropriate callback on the <em>current thread</em>
+     * when it terminates.
+     * <p>
+     * <img width="640" height="256" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingSubscribe.cc.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either {@code onSuccess} or {@code onError} throw, the {@link Throwable} is routed to the
+     *  global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, the {@code onError} consumer is called with an {@link InterruptedException}.
+     *  </dd>
+     * </dl>
+     * @param onSuccess the {@link Consumer} to call if the current {@code Maybe} succeeds
+     * @param onError the {@code Consumer} to call if the current {@code Maybe} signals an error
+     * @throws NullPointerException if {@code onSuccess} or {@code onError} is {@code null}
+     * @since 3.0.0
+     * @see #blockingSubscribe(Consumer, Consumer, Action)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError) {
+        blockingSubscribe(onSuccess, onError, Functions.EMPTY_ACTION);
+    }
+
+    /**
+     * Subscribes to the current {@code Maybe} and calls the appropriate callback on the <em>current thread</em>
+     * when it terminates.
+     * <p>
+     * <img width="640" height="251" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingSubscribe.cca.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either {@code onSuccess}, {@code onError} or {@code onComplete} throw, the {@link Throwable} is routed to the
+     *  global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, the {@code onError} consumer is called with an {@link InterruptedException}.
+     *  </dd>
+     * </dl>
+     * @param onSuccess the {@link Consumer} to call if the current {@code Maybe} succeeds
+     * @param onError the {@code Consumer} to call if the current {@code Maybe} signals an error
+     * @param onComplete the {@linnk Action} to call if the current {@code Maybe} completes without a value
+     * @throws NullPointerException if {@code onSuccess}, {@code onError} or {@code onComplete} is {@code null}
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError, @NonNull Action onComplete) {
+        Objects.requireNonNull(onSuccess, "onSuccess is null");
+        Objects.requireNonNull(onError, "onError is null");
+        Objects.requireNonNull(onComplete, "onComplete is null");
+        BlockingMultiObserver<T> observer = new BlockingMultiObserver<>();
+        subscribe(observer);
+        observer.blockingConsume(onSuccess, onError, onComplete);
+    }
+
+    /**
+     * Subscribes to the current {@code Maybe} and calls the appropriate {@link MaybeObserver} method on the <em>current thread</em>.
+     * <p>
+     * <img width="640" height="398" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingSubscribe.o.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>An {@code onError} signal is delivered to the {@link MaybeObserver#onError(Throwable)} method.
+     *  If any of the {@code MaybeObserver}'s methods throw, the {@link RuntimeException} is propagated to the caller of this method.
+     *  If the current thread is interrupted, an {@link InterruptedException} is delivered to {@code observer.onError}.
+     *  </dd>
+     * </dl>
+     * @param observer the {@code MaybeObserver} to call methods on the current thread
+     * @throws NullPointerException if {@code observer} is {@code null}
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull MaybeObserver<? super T> observer) {
+        Objects.requireNonNull(observer, "observer is null");
+        BlockingDisposableMultiObserver<T> blockingObserver = new BlockingDisposableMultiObserver<>();
+        observer.onSubscribe(blockingObserver);
+        subscribe(blockingObserver);
+        blockingObserver.blockingConsume(observer);
+    }
+
     /**
      * Returns a {@code Maybe} that subscribes to this {@code Maybe} lazily, caches its event
      * and replays it, to all the downstream subscribers.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index c93bfa9282..216d3deb87 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -2947,6 +2947,106 @@ public final T blockingGet() {
         return observer.blockingGet();
     }
 
+    /**
+     * Subscribes to the current {@code Single} and <em>blocks the current thread</em> until it terminates.
+     * <p>
+     * <img width="640" height="329" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.blockingSubscribe.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If the current {@code Single} signals an error,
+     *  the {@link Throwable} is routed to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, an {@link InterruptedException} is routed to the same global error handler.
+     *  </dd>
+     * </dl>
+     * @since 3.0.0
+     * @see #blockingSubscribe(Consumer)
+     * @see #blockingSubscribe(Consumer, Consumer)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe() {
+        blockingSubscribe(Functions.emptyConsumer(), Functions.ERROR_CONSUMER);
+    }
+
+    /**
+     * Subscribes to the current {@code Single} and calls given {@code onSuccess} callback on the <em>current thread</em>
+     * when it completes normally.
+     * <p>
+     * <img width="640" height="351" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.blockingSubscribe.c.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either the current {@code Single} signals an error or {@code onSuccess} throws,
+     *  the respective {@link Throwable} is routed to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, an {@link InterruptedException} is routed to the same global error handler.
+     *  </dd>
+     * </dl>
+     * @param onSuccess the {@link Consumer} to call if the current {@code Single} succeeds
+     * @throws NullPointerException if {@code onSuccess} is {@code null}
+     * @since 3.0.0
+     * @see #blockingSubscribe(Consumer, Consumer)
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess) {
+        blockingSubscribe(onSuccess, Functions.ERROR_CONSUMER);
+    }
+
+    /**
+     * Subscribes to the current {@code Single} and calls the appropriate callback on the <em>current thread</em>
+     * when it terminates.
+     * <p>
+     * <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.blockingSubscribe.cc.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If either {@code onSuccess} or {@code onError} throw, the {@link Throwable} is routed to the
+     *  global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     *  If the current thread is interrupted, the {@code onError} consumer is called with an {@link InterruptedException}.
+     *  </dd>
+     * </dl>
+     * @param onSuccess the {@link Consumer} to call if the current {@code Single} succeeds
+     * @param onError the {@code Consumer} to call if the current {@code Single} signals an error
+     * @throws NullPointerException if {@code onSuccess} or {@code onError} is {@code null}
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError) {
+        Objects.requireNonNull(onSuccess, "onSuccess is null");
+        Objects.requireNonNull(onError, "onError is null");
+        BlockingMultiObserver<T> observer = new BlockingMultiObserver<>();
+        subscribe(observer);
+        observer.blockingConsume(onSuccess, onError, Functions.EMPTY_ACTION);
+    }
+
+    /**
+     * Subscribes to the current {@code Single} and calls the appropriate {@link SingleObserver} method on the <em>current thread</em>.
+     * <p>
+     * <img width="640" height="479" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.blockingSubscribe.o.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code blockingSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>An {@code onError} signal is delivered to the {@link SingleObserver#onError(Throwable)} method.
+     *  If any of the {@code SingleObserver}'s methods throw, the {@link RuntimeException} is propagated to the caller of this method.
+     *  If the current thread is interrupted, an {@link InterruptedException} is delivered to {@code observer.onError}.
+     *  </dd>
+     * </dl>
+     * @param observer the {@code SingleObserver} to call methods on the current thread
+     * @throws NullPointerException if {@code observer} is {@code null}
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void blockingSubscribe(@NonNull SingleObserver<? super T> observer) {
+        Objects.requireNonNull(observer, "observer is null");
+        BlockingDisposableMultiObserver<T> blockingObserver = new BlockingDisposableMultiObserver<>();
+        observer.onSubscribe(blockingObserver);
+        subscribe(blockingObserver);
+        blockingObserver.blockingConsume(observer);
+    }
+
     /**
      * <strong>This method requires advanced knowledge about building operators, please consider
      * other standard composition methods first;</strong>
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingDisposableMultiObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingDisposableMultiObserver.java
new file mode 100644
index 0000000000..da7e289e27
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingDisposableMultiObserver.java
@@ -0,0 +1,154 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.observers;
+
+import java.util.concurrent.CountDownLatch;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.internal.disposables.*;
+import io.reactivex.rxjava3.internal.util.BlockingHelper;
+
+/**
+ * Blocks until the upstream terminates and dispatches the outcome to
+ * the actual observer.
+ *
+ * @param <T> the element type of the source
+ * @since 3.0.0
+ */
+public final class BlockingDisposableMultiObserver<T>
+extends CountDownLatch
+implements MaybeObserver<T>, SingleObserver<T>, CompletableObserver, Disposable {
+
+    T value;
+    Throwable error;
+
+    final SequentialDisposable upstream;
+
+    public BlockingDisposableMultiObserver() {
+        super(1);
+        upstream = new SequentialDisposable();
+    }
+
+    @Override
+    public void dispose() {
+        upstream.dispose();
+        countDown();
+    }
+
+    @Override
+    public boolean isDisposed() {
+        return upstream.isDisposed();
+    }
+
+    @Override
+    public void onSubscribe(@NonNull Disposable d) {
+        DisposableHelper.setOnce(upstream, d);
+    }
+
+    @Override
+    public void onSuccess(@NonNull T t) {
+        this.value = t;
+        upstream.lazySet(Disposable.disposed());
+        countDown();
+    }
+
+    @Override
+    public void onError(@NonNull Throwable e) {
+        this.error = e;
+        upstream.lazySet(Disposable.disposed());
+        countDown();
+    }
+
+    @Override
+    public void onComplete() {
+        upstream.lazySet(Disposable.disposed());
+        countDown();
+    }
+
+    public void blockingConsume(CompletableObserver observer) {
+        if (getCount() != 0) {
+            try {
+                BlockingHelper.verifyNonBlocking();
+                await();
+            } catch (InterruptedException ex) {
+                dispose();
+                observer.onError(ex);
+                return;
+            }
+        }
+        if (isDisposed()) {
+            return;
+        }
+
+        Throwable ex = error;
+        if (ex != null) {
+            observer.onError(ex);
+        } else {
+            observer.onComplete();
+        }
+    }
+
+    public void blockingConsume(SingleObserver<? super T> observer) {
+        if (getCount() != 0) {
+            try {
+                BlockingHelper.verifyNonBlocking();
+                await();
+            } catch (InterruptedException ex) {
+                dispose();
+                observer.onError(ex);
+                return;
+            }
+        }
+        if (isDisposed()) {
+            return;
+        }
+
+        Throwable ex = error;
+        if (ex != null) {
+            observer.onError(ex);
+        } else {
+            observer.onSuccess(value);
+        }
+    }
+
+    public void blockingConsume(MaybeObserver<? super T> observer) {
+        if (getCount() != 0) {
+            try {
+                BlockingHelper.verifyNonBlocking();
+                await();
+            } catch (InterruptedException ex) {
+                dispose();
+                observer.onError(ex);
+                return;
+            }
+        }
+        if (isDisposed()) {
+            return;
+        }
+
+        Throwable ex = error;
+        if (ex != null) {
+            observer.onError(ex);
+        } else {
+            T v = value;
+            if (v == null) {
+                observer.onComplete();
+            } else {
+                observer.onSuccess(v);
+            }
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingMultiObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingMultiObserver.java
index 1f4ee305bd..4945730ab5 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingMultiObserver.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/observers/BlockingMultiObserver.java
@@ -17,7 +17,10 @@
 
 import io.reactivex.rxjava3.core.*;
 import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.*;
 import io.reactivex.rxjava3.internal.util.*;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
 
 /**
  * A combined Observer that awaits the success or error signal via a CountDownLatch.
@@ -143,4 +146,39 @@ public boolean blockingAwait(long timeout, TimeUnit unit) {
         }
         return true;
     }
+
+    /**
+     * Blocks until the source completes and calls the appropriate callback.
+     * @param onSuccess for a succeeding source
+     * @param onError for a failing source
+     * @param onComplete for an empty source
+     */
+    public void blockingConsume(Consumer<? super T> onSuccess, Consumer<? super Throwable> onError, Action onComplete) {
+        try {
+            if (getCount() != 0) {
+                try {
+                    BlockingHelper.verifyNonBlocking();
+                    await();
+                } catch (InterruptedException ex) {
+                    dispose();
+                    onError.accept(ex);
+                    return;
+                }
+            }
+            Throwable ex = error;
+            if (ex != null) {
+                onError.accept(ex);
+                return;
+            }
+            T v = value;
+            if (v != null) {
+                onSuccess.accept(v);
+            } else {
+                onComplete.run();
+            }
+        } catch (Throwable t) {
+            Exceptions.throwIfFatal(t);
+            RxJavaPlugins.onError(t);
+        }
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableBlockingSubscribeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableBlockingSubscribeTest.java
new file mode 100644
index 0000000000..e70aac7157
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableBlockingSubscribeTest.java
@@ -0,0 +1,331 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class CompletableBlockingSubscribeTest {
+
+    @Test
+    public void noArgComplete() {
+        Completable.complete()
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgCompleteAsync() {
+        Completable.complete()
+        .delay(100, TimeUnit.MILLISECONDS)
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Completable.error(new TestException())
+            .blockingSubscribe();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void noArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Completable.error(new TestException())
+            .delay(100, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void oneArgComplete() throws Throwable {
+        Action action = mock(Action.class);
+
+        Completable.complete()
+        .blockingSubscribe(action);
+
+        verify(action).run();
+    }
+
+    @Test
+    public void oneArgCompleteAsync() throws Throwable {
+        Action action = mock(Action.class);
+
+        Completable.complete()
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(action);
+
+        verify(action).run();
+    }
+
+    @Test
+    public void oneArgCompleteFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+            doThrow(new TestException()).when(action).run();
+
+            Completable.complete()
+            .blockingSubscribe(action);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(action).run();
+        });
+    }
+
+    @Test
+    public void oneArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+
+            Completable.error(new TestException())
+            .blockingSubscribe(action);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(action, never()).run();
+        });
+    }
+
+    @Test
+    public void oneArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+
+            Completable.error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe(action);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(action, never()).run();
+        });
+    }
+
+    @Test
+    public void twoArgComplete() throws Throwable {
+        Action action = mock(Action.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Completable.complete()
+        .blockingSubscribe(action, consumer);
+
+        verify(action).run();
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgCompleteAsync() throws Throwable {
+        Action action = mock(Action.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Completable.complete()
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(action, consumer);
+
+        verify(action).run();
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgCompleteFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+            doThrow(new TestException()).when(action).run();
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Completable.complete()
+            .blockingSubscribe(action, consumer);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(action).run();
+            verify(consumer, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void twoArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Completable.error(new TestException())
+            .blockingSubscribe(action, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(action, never()).run();
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Completable.error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe(action, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(action, never()).run();
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgErrorFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action action = mock(Action.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+            doThrow(new TestException()).when(consumer).accept(any());
+
+            Completable.error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe(action, consumer);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(action, never()).run();
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgInterrupted() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action onDispose = mock(Action.class);
+
+            Action action = mock(Action.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Thread.currentThread().interrupt();
+
+            Completable.never()
+            .doOnDispose(onDispose)
+            .blockingSubscribe(action, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(onDispose).run();
+            verify(action, never()).run();
+            verify(consumer).accept(any(InterruptedException.class));
+        });
+    }
+
+    @Test
+    public void observerComplete() {
+        TestObserver<Void> to = new TestObserver<>();
+
+        Completable.complete()
+        .blockingSubscribe(to);
+
+        to.assertResult();
+    }
+
+    @Test
+    public void observerCompleteAsync() {
+        TestObserver<Void> to = new TestObserver<>();
+
+        Completable.complete()
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+        .blockingSubscribe(to);
+
+        to.assertResult();
+    }
+
+    @Test
+    public void observerError() {
+        TestObserver<Void> to = new TestObserver<>();
+
+        Completable.error(new TestException())
+        .blockingSubscribe(to);
+
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void observerErrorAsync() {
+        TestObserver<Void> to = new TestObserver<>();
+
+        Completable.error(new TestException())
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+        .blockingSubscribe(to);
+
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void observerDispose() throws Throwable {
+        Action onDispose = mock(Action.class);
+
+        TestObserver<Void> to = new TestObserver<>();
+        to.dispose();
+
+        Completable.never()
+        .doOnDispose(onDispose)
+        .blockingSubscribe(to);
+
+        to.assertEmpty();
+
+        verify(onDispose).run();
+    }
+
+    @Test
+    public void ovserverInterrupted() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action onDispose = mock(Action.class);
+
+            TestObserver<Void> to = new TestObserver<>();
+
+            Thread.currentThread().interrupt();
+
+            Completable.never()
+            .doOnDispose(onDispose)
+            .blockingSubscribe(to);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(onDispose).run();
+            to.assertFailure(InterruptedException.class);
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeBlockingSubscribeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeBlockingSubscribeTest.java
new file mode 100644
index 0000000000..647d385eef
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeBlockingSubscribeTest.java
@@ -0,0 +1,502 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Maybe;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeBlockingSubscribeTest {
+
+    @Test
+    public void noArgSuccess() {
+        Maybe.just(1)
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgSuccessAsync() {
+        Maybe.just(1)
+        .delay(100, TimeUnit.MILLISECONDS)
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgEmpty() {
+        Maybe.empty()
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgEmptyAsync() {
+        Maybe.empty()
+        .delay(100, TimeUnit.MILLISECONDS)
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Maybe.error(new TestException())
+            .blockingSubscribe();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void noArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Maybe.error(new TestException())
+            .delay(100, TimeUnit.MILLISECONDS, Schedulers.computation())
+            .blockingSubscribe();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void oneArgSuccess() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+
+        Maybe.just(1)
+        .blockingSubscribe(success);
+
+        verify(success).accept(1);
+    }
+
+    @Test
+    public void oneArgSuccessAsync() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+
+        Maybe.just(1)
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(success);
+
+        verify(success).accept(1);
+    }
+
+    @Test
+    public void oneArgEmpty() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+
+        Maybe.<Integer>empty()
+        .blockingSubscribe(success);
+
+        verify(success, never()).accept(any());
+    }
+
+    @Test
+    public void oneArgEmptyAsync() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+
+        Maybe.<Integer>empty()
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(success);
+
+        verify(success, never()).accept(any());
+    }
+
+    @Test
+    public void oneArgSuccessFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            doThrow(new TestException()).when(success).accept(any());
+
+            Maybe.just(1)
+            .blockingSubscribe(success);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success).accept(1);
+        });
+    }
+
+    @Test
+    public void oneArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+
+            Maybe.<Integer>error(new TestException())
+            .blockingSubscribe(success);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void oneArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+
+            Maybe.<Integer>error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+            .blockingSubscribe(success);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void twoArgSuccess() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Maybe.just(1)
+        .blockingSubscribe(success, consumer);
+
+        verify(success).accept(1);
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgSuccessAsync() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Maybe.just(1)
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(success, consumer);
+
+        verify(success).accept(any());
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgEmpty() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Maybe.<Integer>empty()
+        .blockingSubscribe(success, consumer);
+
+        verify(success, never()).accept(any());
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgEmptyAsync() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Maybe.<Integer>empty()
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(success, consumer);
+
+        verify(success, never()).accept(any());
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgSuccessFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            doThrow(new TestException()).when(success).accept(any());
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Maybe.just(1)
+            .blockingSubscribe(success, consumer);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success).accept(any());
+            verify(consumer, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void twoArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Maybe.<Integer>error(new TestException())
+            .blockingSubscribe(success, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Maybe.<Integer>error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+            .blockingSubscribe(success, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgErrorFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+            doThrow(new TestException()).when(consumer).accept(any());
+
+            Maybe.<Integer>error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+            .blockingSubscribe(success, consumer);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void threeArgSuccess() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+        Action action = mock(Action.class);
+
+        Maybe.just(1)
+        .blockingSubscribe(success, consumer, action);
+
+        verify(success).accept(any());
+        verify(consumer, never()).accept(any(Throwable.class));
+        verify(action, never()).run();
+    }
+
+    @Test
+    public void threeArgEmpty() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+        Action action = mock(Action.class);
+
+        Maybe.<Integer>empty()
+        .blockingSubscribe(success, consumer, action);
+
+        verify(success, never()).accept(any());
+        verify(consumer, never()).accept(any(Throwable.class));
+        verify(action).run();
+    }
+
+    @Test
+    public void threeArgError() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+        Action action = mock(Action.class);
+
+        Maybe.<Integer>error(new TestException())
+        .blockingSubscribe(success, consumer, action);
+
+        verify(success, never()).accept(any());
+        verify(consumer).accept(any(TestException.class));
+        verify(action, never()).run();
+    }
+
+    @Test
+    public void threeArgEmptyFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Action action = mock(Action.class);
+            doThrow(new TestException()).when(action).run();
+
+            Maybe.<Integer>empty()
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+            .blockingSubscribe(success, consumer, action);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+            verify(consumer, never()).accept(any());
+            verify(action).run();
+        });
+    }
+
+    @Test
+    public void threeArgInterrupted() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action onDispose = mock(Action.class);
+
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+            Action action = mock(Action.class);
+
+            Thread.currentThread().interrupt();
+
+            Maybe.<Integer>never()
+            .doOnDispose(onDispose)
+            .blockingSubscribe(success, consumer, action);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(onDispose).run();
+            verify(success, never()).accept(any());
+            verify(action, never()).run();
+            verify(consumer).accept(any(InterruptedException.class));
+        });
+    }
+
+    @Test
+    public void observerSuccess() {
+        TestObserver<Integer> to = new TestObserver<>();
+
+        Maybe.just(1)
+        .blockingSubscribe(to);
+
+        to.assertResult(1);
+    }
+
+    @Test
+    public void observerSuccessAsync() {
+        TestObserver<Integer> to = new TestObserver<>();
+
+        Maybe.just(1)
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+        .blockingSubscribe(to);
+
+        to.assertResult(1);
+    }
+
+    @Test
+    public void observerEmpty() {
+        TestObserver<Integer> to = new TestObserver<>();
+
+        Maybe.<Integer>empty()
+        .blockingSubscribe(to);
+
+        to.assertResult();
+    }
+
+    @Test
+    public void observerEmptyAsync() {
+        TestObserver<Integer> to = new TestObserver<>();
+
+        Maybe.<Integer>empty()
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+        .blockingSubscribe(to);
+
+        to.assertResult();
+    }
+
+    @Test
+    public void observerError() {
+        TestObserver<Object> to = new TestObserver<>();
+
+        Maybe.error(new TestException())
+        .blockingSubscribe(to);
+
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void observerErrorAsync() {
+        TestObserver<Object> to = new TestObserver<>();
+
+        Maybe.error(new TestException())
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation())
+        .blockingSubscribe(to);
+
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void observerDispose() throws Throwable {
+        Action onDispose = mock(Action.class);
+
+        TestObserver<Object> to = new TestObserver<>();
+        to.dispose();
+
+        Maybe.never()
+        .doOnDispose(onDispose)
+        .blockingSubscribe(to);
+
+        to.assertEmpty();
+
+        verify(onDispose).run();
+    }
+
+    @Test
+    public void ovserverInterrupted() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action onDispose = mock(Action.class);
+
+            TestObserver<Object> to = new TestObserver<>();
+
+            Thread.currentThread().interrupt();
+
+            Maybe.never()
+            .doOnDispose(onDispose)
+            .blockingSubscribe(to);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(onDispose).run();
+            to.assertFailure(InterruptedException.class);
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleBlockingSubscribeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleBlockingSubscribeTest.java
new file mode 100644
index 0000000000..50eceede5c
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleBlockingSubscribeTest.java
@@ -0,0 +1,343 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleBlockingSubscribeTest {
+
+    @Test
+    public void noArgSuccess() {
+        Single.just(1)
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgSuccessAsync() {
+        Single.just(1)
+        .delay(100, TimeUnit.MILLISECONDS)
+        .blockingSubscribe();
+    }
+
+    @Test
+    public void noArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new TestException())
+            .blockingSubscribe();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void noArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new TestException())
+            .delay(100, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void oneArgSuccess() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+
+        Single.just(1)
+        .blockingSubscribe(success);
+
+        verify(success).accept(1);
+    }
+
+    @Test
+    public void oneArgSuccessAsync() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+
+        Single.just(1)
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(success);
+
+        verify(success).accept(1);
+    }
+
+    @Test
+    public void oneArgSuccessFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            doThrow(new TestException()).when(success).accept(any());
+
+            Single.just(1)
+            .blockingSubscribe(success);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success).accept(1);
+        });
+    }
+
+    @Test
+    public void oneArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+
+            Single.<Integer>error(new TestException())
+            .blockingSubscribe(success);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void oneArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+
+            Single.<Integer>error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe(success);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void twoArgSuccess() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Single.just(1)
+        .blockingSubscribe(success, consumer);
+
+        verify(success).accept(1);
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgSuccessAsync() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<Integer> success = mock(Consumer.class);
+        @SuppressWarnings("unchecked")
+        Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+        Single.just(1)
+        .delay(50, TimeUnit.MILLISECONDS)
+        .blockingSubscribe(success, consumer);
+
+        verify(success).accept(any());
+        verify(consumer, never()).accept(any());
+    }
+
+    @Test
+    public void twoArgSuccessFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            doThrow(new TestException()).when(success).accept(any());
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Single.just(1)
+            .blockingSubscribe(success, consumer);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success).accept(any());
+            verify(consumer, never()).accept(any());
+        });
+    }
+
+    @Test
+    public void twoArgError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Single.<Integer>error(new TestException())
+            .blockingSubscribe(success, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgErrorAsync() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Single.<Integer>error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe(success, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgErrorFails() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+            doThrow(new TestException()).when(consumer).accept(any());
+
+            Single.<Integer>error(new TestException())
+            .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+            .blockingSubscribe(success, consumer);
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(TestException.class));
+        });
+    }
+
+    @Test
+    public void twoArgInterrupted() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action onDispose = mock(Action.class);
+
+            @SuppressWarnings("unchecked")
+            Consumer<Integer> success = mock(Consumer.class);
+            @SuppressWarnings("unchecked")
+            Consumer<? super Throwable> consumer = mock(Consumer.class);
+
+            Thread.currentThread().interrupt();
+
+            Single.<Integer>never()
+            .doOnDispose(onDispose)
+            .blockingSubscribe(success, consumer);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(onDispose).run();
+            verify(success, never()).accept(any());
+            verify(consumer).accept(any(InterruptedException.class));
+        });
+    }
+
+    @Test
+    public void observerSuccess() {
+        TestObserver<Integer> to = new TestObserver<>();
+
+        Single.just(1)
+        .blockingSubscribe(to);
+
+        to.assertResult(1);
+    }
+
+    @Test
+    public void observerSuccessAsync() {
+        TestObserver<Integer> to = new TestObserver<>();
+
+        Single.just(1)
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+        .blockingSubscribe(to);
+
+        to.assertResult(1);
+    }
+
+    @Test
+    public void observerError() {
+        TestObserver<Object> to = new TestObserver<>();
+
+        Single.error(new TestException())
+        .blockingSubscribe(to);
+
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void observerErrorAsync() {
+        TestObserver<Object> to = new TestObserver<>();
+
+        Single.error(new TestException())
+        .delay(50, TimeUnit.MILLISECONDS, Schedulers.computation(), true)
+        .blockingSubscribe(to);
+
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void observerDispose() throws Throwable {
+        Action onDispose = mock(Action.class);
+
+        TestObserver<Object> to = new TestObserver<>();
+        to.dispose();
+
+        Single.never()
+        .doOnDispose(onDispose)
+        .blockingSubscribe(to);
+
+        to.assertEmpty();
+
+        verify(onDispose).run();
+    }
+
+    @Test
+    public void ovserverInterrupted() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Action onDispose = mock(Action.class);
+
+            TestObserver<Object> to = new TestObserver<>();
+
+            Thread.currentThread().interrupt();
+
+            Single.never()
+            .doOnDispose(onDispose)
+            .blockingSubscribe(to);
+
+            assertTrue("" + errors, errors.isEmpty());
+
+            verify(onDispose).run();
+            to.assertFailure(InterruptedException.class);
+        });
+    }
+}

From 13473da61366945f49aed5a29729841836abf2ab Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Fri, 24 Jan 2020 17:36:18 +0100
Subject: [PATCH 10/37] 3.x: Fix many marbles in Maybe (#6866)

---
 .../java/io/reactivex/rxjava3/core/Maybe.java | 80 ++++++++++++-------
 1 file changed, 53 insertions(+), 27 deletions(-)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 0d0d6f5473..375a439e65 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -562,6 +562,8 @@ public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends
     /**
      * Provides an API (via a cold {@code Maybe}) that bridges the reactive world with the callback-style world.
      * <p>
+     * <img width="640" height="499" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.create.png" alt="">
+     * <p>
      * Example:
      * <pre><code>
      * Maybe.&lt;Event&gt;create(emitter -&gt; {
@@ -615,6 +617,8 @@ public static <T> Maybe<T> create(@NonNull MaybeOnSubscribe<T> onSubscribe) {
     /**
      * Calls a {@link Supplier} for each individual {@link MaybeObserver} to return the actual {@link MaybeSource} source to
      * be subscribed to.
+     * <p>
+     * <img width="640" height="498" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.defer.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code defer} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -683,7 +687,7 @@ public static <T> Maybe<T> error(@NonNull Throwable throwable) {
      * Returns a {@code Maybe} that invokes a {@link MaybeObserver}'s {@link MaybeObserver#onError onError} method when the
      * {@code MaybeObserver} subscribes to it.
      * <p>
-     * <img width="640" height="190" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/error.png" alt="">
+     * <img width="640" height="440" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.error.f.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -708,6 +712,8 @@ public static <T> Maybe<T> error(@NonNull Supplier<? extends Throwable> supplier
     /**
      * Returns a {@code Maybe} instance that runs the given {@link Action} for each subscriber and
      * emits either its exception or simply completes.
+     * <p>
+     * <img width="640" height="287" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromAction.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code fromAction} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -734,7 +740,8 @@ public static <T> Maybe<T> fromAction(@NonNull Action action) {
 
     /**
      * Wraps a {@link CompletableSource} into a {@code Maybe}.
-     *
+     * <p>
+     * <img width="640" height="280" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromCompletable.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code fromCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -754,7 +761,8 @@ public static <T> Maybe<T> fromCompletable(@NonNull CompletableSource completabl
 
     /**
      * Wraps a {@link SingleSource} into a {@code Maybe}.
-     *
+     * <p>
+     * <img width="640" height="344" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromSingle.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code fromSingle} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -778,6 +786,8 @@ public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
      * considering a {@code null} result from the {@code Callable} as indication for valueless completion
      * via {@code onComplete}.
      * <p>
+     * <img width="640" height="183" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromCallable.png" alt="">
+     * <p>
      * This operator allows you to defer the execution of the given {@code Callable} until a {@code MaybeObserver}
      * subscribes to the  returned {@code Maybe}. In other terms, this source operator evaluates the given
      * {@code Callable} "lazily".
@@ -820,7 +830,7 @@ public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
     /**
      * Converts a {@link Future} into a {@code Maybe}, treating a {@code null} result as an indication of emptiness.
      * <p>
-     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/from.Future.png" alt="">
+     * <img width="640" height="204" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromFuture.png" alt="">
      * <p>
      * The operator calls {@link Future#get()}, which is a blocking method, on the subscription thread.
      * It is recommended applying {@link #subscribeOn(Scheduler)} to move this blocking wait to a
@@ -854,7 +864,7 @@ public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
     /**
      * Converts a {@link Future} into a {@code Maybe}, with a timeout on the {@code Future}.
      * <p>
-     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/from.Future.png" alt="">
+     * <img width="640" height="176" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromFuture.t.png" alt="">
      * <p>
      * The operator calls {@link Future#get(long, TimeUnit)}, which is a blocking method, on the subscription thread.
      * It is recommended applying {@link #subscribeOn(Scheduler)} to move this blocking wait to a
@@ -893,6 +903,8 @@ public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
     /**
      * Returns a {@code Maybe} instance that runs the given {@link Runnable} for each subscriber and
      * emits either its exception or simply completes.
+     * <p>
+     * <img width="640" height="287" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromRunnable.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code fromRunnable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -989,6 +1001,8 @@ public static <T> Maybe<T> fromRunnable(@NonNull Runnable run) {
     /**
      * Merges an {@link Iterable} sequence of {@link MaybeSource} instances into a single {@link Flowable} sequence,
      * running all {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="301" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.i.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -1025,6 +1039,8 @@ public static <T> Flowable<T> merge(@NonNull Iterable<@NonNull ? extends MaybeSo
     /**
      * Merges a {@link Publisher} sequence of {@link MaybeSource} instances into a single {@link Flowable} sequence,
      * running all {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.p.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -1061,6 +1077,8 @@ public static <T> Flowable<T> merge(@NonNull Publisher<@NonNull ? extends MaybeS
     /**
      * Merges a {@link Publisher} sequence of {@link MaybeSource} instances into a single {@link Flowable} sequence,
      * running at most maxConcurrency {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="260" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.pn.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -1134,7 +1152,7 @@ public static <T> Maybe<T> merge(@NonNull MaybeSource<? extends MaybeSource<? ex
     /**
      * Flattens two {@link MaybeSource}s into a single {@link Flowable}, without any transformation.
      * <p>
-     * <img width="640" height="483" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.png" alt="">
+     * <img width="640" height="279" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.2.png" alt="">
      * <p>
      * You can combine items emitted by multiple {@code MaybeSource}s so that they appear as a single {@code Flowable}, by
      * using the {@code merge} method.
@@ -1183,7 +1201,7 @@ public static <T> Flowable<T> merge(
     /**
      * Flattens three {@link MaybeSource}s into a single {@link Flowable}, without any transformation.
      * <p>
-     * <img width="640" height="483" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.png" alt="">
+     * <img width="640" height="301" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.3.png" alt="">
      * <p>
      * You can combine items emitted by multiple {@code MaybeSource}s so that they appear as a single {@code Flowable}, by using
      * the {@code merge} method.
@@ -1236,7 +1254,7 @@ public static <T> Flowable<T> merge(
     /**
      * Flattens four {@link MaybeSource}s into a single {@link Flowable}, without any transformation.
      * <p>
-     * <img width="640" height="483" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.png" alt="">
+     * <img width="640" height="289" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.4.png" alt="">
      * <p>
      * You can combine items emitted by multiple {@code MaybeSource}s so that they appear as a single {@code Flowable}, by using
      * the {@code merge} method.
@@ -1292,6 +1310,8 @@ public static <T> Flowable<T> merge(
     /**
      * Merges an array sequence of {@link MaybeSource} instances into a single {@link Flowable} sequence,
      * running all {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="272" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeArray.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -1340,12 +1360,12 @@ public static <T> Flowable<T> mergeArray(MaybeSource<? extends T>... sources) {
      * successfully emitted items from each of the source {@code MaybeSource}s without being interrupted by an error
      * notification from one of them.
      * <p>
+     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeArrayDelayError.png" alt="">
+     * <p>
      * This behaves like {@link #merge(Publisher)} except that if any of the merged {@code MaybeSource}s notify of an
      * error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain from propagating that
      * error notification until all of the merged {@code MaybeSource}s have finished emitting items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
-     * <p>
      * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
@@ -1381,11 +1401,13 @@ public static <T> Flowable<T> mergeArrayDelayError(@NonNull MaybeSource<? extend
      * successfully emitted items from each of the source {@code MaybeSource}s without being interrupted by an error
      * notification from one of them.
      * <p>
+     * <img width="640" height="467" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.i.png" alt="">
+     * <p>
      * This behaves like {@link #merge(Publisher)} except that if any of the merged {@code MaybeSource}s notify of an
      * error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain from propagating that
      * error notification until all of the merged {@code MaybeSource}s have finished emitting items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
+     * <img width="640" height="467" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.i.png" alt="">
      * <p>
      * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
@@ -1417,12 +1439,12 @@ public static <T> Flowable<T> mergeDelayError(@NonNull Iterable<@NonNull ? exten
      * receive all successfully emitted items from all of the source {@code MaybeSource}s without being interrupted by
      * an error notification from one of them or even the main {@code Publisher}.
      * <p>
+     * <img width="640" height="456" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.p.png" alt="">
+     * <p>
      * This behaves like {@link #merge(Publisher)} except that if any of the merged {@code MaybeSource}s notify of an
      * error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain from propagating that
      * error notification until all of the merged {@code MaybeSource}s and the main {@code Publisher} have finished emitting items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
-     * <p>
      * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
@@ -1453,12 +1475,12 @@ public static <T> Flowable<T> mergeDelayError(@NonNull Publisher<@NonNull ? exte
      * receive all successfully emitted items from all of the source {@code MaybeSource}s without being interrupted by
      * an error notification from one of them or even the main {@code Publisher} as well as limiting the total number of active {@code MaybeSource}s.
      * <p>
+     * <img width="640" height="429" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.pn.png" alt="">
+     * <p>
      * This behaves like {@link #merge(Publisher, int)} except that if any of the merged {@code MaybeSource}s notify of an
      * error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain from propagating that
      * error notification until all of the merged {@code MaybeSource}s and the main {@code Publisher} have finished emitting items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
-     * <p>
      * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
@@ -1495,12 +1517,12 @@ public static <T> Flowable<T> mergeDelayError(@NonNull Publisher<@NonNull ? exte
      * successfully emitted items from each of the source {@code MaybeSource}s without being interrupted by an error
      * notification from one of them.
      * <p>
+     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.2.png" alt="">
+     * <p>
      * This behaves like {@link #merge(MaybeSource, MaybeSource)} except that if any of the merged {@code MaybeSource}s
      * notify of an error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain from
      * propagating that error notification until all of the merged {@code MaybeSource}s have finished emitting items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
-     * <p>
      * Even if both merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
@@ -1534,13 +1556,13 @@ public static <T> Flowable<T> mergeDelayError(@NonNull MaybeSource<? extends T>
      * successfully emitted items from all of the source {@code MaybeSource}s without being interrupted by an error
      * notification from one of them.
      * <p>
+     * <img width="640" height="467" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.3.png" alt="">
+     * <p>
      * This behaves like {@link #merge(MaybeSource, MaybeSource, MaybeSource)} except that if any of the merged
      * {@code MaybeSource}s notify of an error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain
      * from propagating that error notification until all of the merged {@code MaybeSource}s have finished emitting
      * items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
-     * <p>
      * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
@@ -1578,13 +1600,13 @@ public static <T> Flowable<T> mergeDelayError(@NonNull MaybeSource<? extends T>
      * successfully emitted items from all of the source {@code MaybeSource}s without being interrupted by an error
      * notification from one of them.
      * <p>
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeDelayError.4.png" alt="">
+     * <p>
      * This behaves like {@link #merge(MaybeSource, MaybeSource, MaybeSource, MaybeSource)} except that if any of
      * the merged {@code MaybeSource}s notify of an error via {@link Subscriber#onError onError}, {@code mergeDelayError}
      * will refrain from propagating that error notification until all of the merged {@code MaybeSource}s have finished
      * emitting items.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeDelayError.png" alt="">
-     * <p>
      * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
@@ -1649,7 +1671,7 @@ public static <T> Maybe<T> never() {
      * Returns a {@link Single} that emits a {@link Boolean} value that indicates whether two {@link MaybeSource} sequences are the
      * same by comparing the items emitted by each {@code MaybeSource} pairwise.
      * <p>
-     * <img width="640" height="385" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sequenceEqual.png" alt="">
+     * <img width="640" height="196" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.sequenceEqual.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code sequenceEqual} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1677,7 +1699,7 @@ public static <T> Single<Boolean> sequenceEqual(@NonNull MaybeSource<? extends T
      * same by comparing the items emitted by each {@code MaybeSource} pairwise based on the results of a specified
      * equality function.
      * <p>
-     * <img width="640" height="385" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sequenceEqual.png" alt="">
+     * <img width="640" height="247" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.sequenceEqual.f.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code sequenceEqual} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1709,7 +1731,7 @@ public static <T> Single<Boolean> sequenceEqual(@NonNull MaybeSource<? extends T
     /**
      * Returns a {@code Maybe} that emits {@code 0L} after a specified delay.
      * <p>
-     * <img width="640" height="200" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/timer.png" alt="">
+     * <img width="640" height="391" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timer.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code timer} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -1733,7 +1755,7 @@ public static Maybe<Long> timer(long delay, @NonNull TimeUnit unit) {
     /**
      * Returns a {@code Maybe} that emits {@code 0L} after a specified delay on a specified {@link Scheduler}.
      * <p>
-     * <img width="640" height="200" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/timer.s.png" alt="">
+     * <img width="640" height="392" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timer.s.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
@@ -1762,6 +1784,8 @@ public static Maybe<Long> timer(long delay, @NonNull TimeUnit unit, @NonNull Sch
     /**
      * <strong>Advanced use only:</strong> creates a {@code Maybe} instance without
      * any safeguards by using a callback that is called with a {@link MaybeObserver}.
+     * <p>
+     * <img width="640" height="262" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.unsafeCreate.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code unsafeCreate} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1787,7 +1811,7 @@ public static <T> Maybe<T> unsafeCreate(@NonNull MaybeSource<T> onSubscribe) {
      * Constructs a {@code Maybe} that creates a dependent resource object which is disposed of when the
      * generated {@link MaybeSource} terminates or the downstream calls dispose().
      * <p>
-     * <img width="640" height="400" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/using.png" alt="">
+     * <img width="640" height="378" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.using.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code using} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1818,7 +1842,7 @@ public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSuppl
      * Constructs a {@code Maybe} that creates a dependent resource object which is disposed first ({code eager == true})
      * when the generated {@link MaybeSource} terminates or the downstream disposes; or after ({code eager == false}).
      * <p>
-     * <img width="640" height="400" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/using.png" alt="">
+     * <img width="640" height="323" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.using.b.png" alt="">
      * <p>
      * Eager disposal is particularly appropriate for a synchronous {@code Maybe} that reuses resources. {@code disposeAction} will
      * only be called once per subscription.
@@ -1859,6 +1883,8 @@ public static <T, D> Maybe<T> using(@NonNull Supplier<? extends D> resourceSuppl
     /**
      * Wraps a {@link MaybeSource} instance into a new {@code Maybe} instance if not already a {@code Maybe}
      * instance.
+     * <p>
+     * <img width="640" height="232" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.wrap.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code wrap} does not operate by default on a particular {@link Scheduler}.</dd>

From ad1840b1b591206e5eeb10c07b1b126fbbac3560 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Fri, 24 Jan 2020 22:44:22 +0100
Subject: [PATCH 11/37] 3.x: Add onErrorComplete to Flowable, Observable and
 Single (#6867)

* 3.x: Add onErrorComplete to F/O/S

* Add version tags.
---
 .../io/reactivex/rxjava3/core/Flowable.java   |  54 ++++++-
 .../java/io/reactivex/rxjava3/core/Maybe.java |   4 +
 .../io/reactivex/rxjava3/core/Observable.java |  43 ++++++
 .../io/reactivex/rxjava3/core/Single.java     |  43 ++++++
 .../flowable/FlowableOnErrorComplete.java     | 107 +++++++++++++
 .../operators/maybe/MaybeOnErrorComplete.java |   7 +-
 .../observable/ObservableOnErrorComplete.java | 106 +++++++++++++
 .../single/SingleOnErrorComplete.java         |  43 ++++++
 .../flowable/FlowableOnErrorCompleteTest.java | 143 ++++++++++++++++++
 .../ObservableOnErrorCompleteTest.java        | 134 ++++++++++++++++
 .../single/SingleOnErrorCompleteTest.java     | 113 ++++++++++++++
 11 files changed, 793 insertions(+), 4 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorComplete.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorComplete.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorComplete.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorCompleteTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorCompleteTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorCompleteTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 0106f42ce9..a627eb3474 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -19,6 +19,7 @@
 import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
+import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.exceptions.*;
 import io.reactivex.rxjava3.flowables.*;
@@ -28,7 +29,7 @@
 import io.reactivex.rxjava3.internal.jdk8.*;
 import io.reactivex.rxjava3.internal.operators.flowable.*;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
-import io.reactivex.rxjava3.internal.operators.observable.ObservableFromPublisher;
+import io.reactivex.rxjava3.internal.operators.observable.*;
 import io.reactivex.rxjava3.internal.schedulers.ImmediateThinScheduler;
 import io.reactivex.rxjava3.internal.subscribers.*;
 import io.reactivex.rxjava3.internal.util.*;
@@ -12308,6 +12309,57 @@ public final Flowable<T> onBackpressureLatest() {
         return RxJavaPlugins.onAssembly(new FlowableOnBackpressureLatest<>(this));
     }
 
+    /**
+     * Returns a {@code Flowable} instance that if the current {@code Flowable} emits an error, it will emit an {@code onComplete}
+     * and swallow the throwable.
+     * <p>
+     * <img width="640" height="372" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.onErrorComplete.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator doesn't interfere with backpressure which is determined by the current {@code Flowable}'s backpressure
+     *  behavior.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @return the new {@code Flowable} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
+    @NonNull
+    public final Flowable<T> onErrorComplete() {
+        return onErrorComplete(Functions.alwaysTrue());
+    }
+
+    /**
+     * Returns a {@code Flowable} instance that if the current {@code Flowable} emits an error and the predicate returns
+     * {@code true}, it will emit an {@code onComplete} and swallow the throwable.
+     * <p>
+     * <img width="640" height="201" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.onErrorComplete.f.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator doesn't interfere with backpressure which is determined by the current {@code Flowable}'s backpressure
+     *  behavior.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param predicate the predicate to call when an {@link Throwable} is emitted which should return {@code true}
+     * if the {@code Throwable} should be swallowed and replaced with an {@code onComplete}.
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code predicate} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Flowable<T> onErrorComplete(@NonNull Predicate<? super Throwable> predicate) {
+        Objects.requireNonNull(predicate, "predicate is null");
+
+        return RxJavaPlugins.onAssembly(new FlowableOnErrorComplete<>(this, predicate));
+    }
+
     /**
      * Resumes the flow with a {@link Publisher} returned for the failure {@link Throwable} of the current {@code Flowable} by a
      * function instead of signaling the error via {@code onError}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 375a439e65..1d385ce148 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -4042,6 +4042,8 @@ public final Single<T> toSingle() {
     /**
      * Returns a {@code Maybe} instance that if this {@code Maybe} emits an error, it will emit an {@code onComplete}
      * and swallow the throwable.
+     * <p>
+     * <img width="640" height="372" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.onErrorComplete.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4058,6 +4060,8 @@ public final Maybe<T> onErrorComplete() {
     /**
      * Returns a {@code Maybe} instance that if this {@code Maybe} emits an error and the predicate returns
      * {@code true}, it will emit an {@code onComplete} and swallow the throwable.
+     * <p>
+     * <img width="640" height="220" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.onErrorComplete.f.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index 57456a9545..f599ce0eeb 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -10346,6 +10346,49 @@ public final <U> Observable<U> ofType(@NonNull Class<U> clazz) {
         return filter(Functions.isInstanceOf(clazz)).cast(clazz);
     }
 
+    /**
+     * Returns an {@code Observable} instance that if the current {@code Observable} emits an error, it will emit an {@code onComplete}
+     * and swallow the throwable.
+     * <p>
+     * <img width="640" height="373" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.onErrorComplete.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @return the new {@code Observable} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Observable<T> onErrorComplete() {
+        return onErrorComplete(Functions.alwaysTrue());
+    }
+
+    /**
+     * Returns an {@code Observable} instance that if the current {@code Observable} emits an error and the predicate returns
+     * {@code true}, it will emit an {@code onComplete} and swallow the throwable.
+     * <p>
+     * <img width="640" height="215" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.onErrorComplete.f.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param predicate the predicate to call when an {@link Throwable} is emitted which should return {@code true}
+     * if the {@code Throwable} should be swallowed and replaced with an {@code onComplete}.
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code predicate} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Observable<T> onErrorComplete(@NonNull Predicate<? super Throwable> predicate) {
+        Objects.requireNonNull(predicate, "predicate is null");
+
+        return RxJavaPlugins.onAssembly(new ObservableOnErrorComplete<>(this, predicate));
+    }
+
     /**
      * Resumes the flow with an {@link ObservableSource} returned for the failure {@link Throwable} of the current {@code Observable} by a
      * function instead of signaling the error via {@code onError}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 216d3deb87..f6e41cee5c 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -3439,6 +3439,49 @@ public final Single<T> onErrorResumeWith(@NonNull SingleSource<? extends T> fall
         return onErrorResumeNext(Functions.justFunction(fallback));
     }
 
+    /**
+     * Returns a {@link Maybe} instance that if the current {@code Single} emits an error, it will emit an {@code onComplete}
+     * and swallow the throwable.
+     * <p>
+     * <img width="640" height="554" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorComplete.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @return the new {@code Maybe} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Maybe<T> onErrorComplete() {
+        return onErrorComplete(Functions.alwaysTrue());
+    }
+
+    /**
+     * Returns a {@link Maybe} instance that if this {@code Single} emits an error and the predicate returns
+     * {@code true}, it will emit an {@code onComplete} and swallow the throwable.
+     * <p>
+     * <img width="640" height="220" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorComplete.f.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param predicate the predicate to call when an {@link Throwable} is emitted which should return {@code true}
+     * if the {@code Throwable} should be swallowed and replaced with an {@code onComplete}.
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code predicate} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Maybe<T> onErrorComplete(@NonNull Predicate<? super Throwable> predicate) {
+        Objects.requireNonNull(predicate, "predicate is null");
+
+        return RxJavaPlugins.onAssembly(new SingleOnErrorComplete<>(this, predicate));
+    }
+
     /**
      * Resumes the flow with a {@link SingleSource} returned for the failure {@link Throwable} of the current {@code Single} by a
      * function instead of signaling the error via {@code onError}.
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorComplete.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorComplete.java
new file mode 100644
index 0000000000..c477917f35
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorComplete.java
@@ -0,0 +1,107 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import org.reactivestreams.*;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.functions.Predicate;
+import io.reactivex.rxjava3.internal.subscriptions.SubscriptionHelper;
+
+/**
+ * Emits an onComplete if the source emits an onError and the predicate returns true for
+ * that Throwable.
+ * 
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class FlowableOnErrorComplete<T> extends AbstractFlowableWithUpstream<T, T> {
+
+    final Predicate<? super Throwable> predicate;
+
+    public FlowableOnErrorComplete(Flowable<T> source,
+            Predicate<? super Throwable> predicate) {
+        super(source);
+        this.predicate = predicate;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super T> observer) {
+        source.subscribe(new OnErrorCompleteSubscriber<>(observer, predicate));
+    }
+
+    public static final class OnErrorCompleteSubscriber<T>
+    implements FlowableSubscriber<T>, Subscription {
+
+        final Subscriber<? super T> downstream;
+
+        final Predicate<? super Throwable> predicate;
+
+        Subscription upstream;
+
+        public OnErrorCompleteSubscriber(Subscriber<? super T> actual, Predicate<? super Throwable> predicate) {
+            this.downstream = actual;
+            this.predicate = predicate;
+        }
+
+        @Override
+        public void onSubscribe(Subscription s) {
+            if (SubscriptionHelper.validate(this.upstream, s)) {
+                this.upstream = s;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onNext(T value) {
+            downstream.onNext(value);
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            boolean b;
+
+            try {
+                b = predicate.test(e);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                downstream.onError(new CompositeException(e, ex));
+                return;
+            }
+
+            if (b) {
+                downstream.onComplete();
+            } else {
+                downstream.onError(e);
+            }
+        }
+
+        @Override
+        public void onComplete() {
+            downstream.onComplete();
+        }
+
+        @Override
+        public void cancel() {
+            upstream.cancel();
+        }
+
+        @Override
+        public void request(long n) {
+            upstream.request(n);
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorComplete.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorComplete.java
index 8792a93cc5..277e207eaf 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorComplete.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorComplete.java
@@ -37,10 +37,11 @@ public MaybeOnErrorComplete(MaybeSource<T> source,
 
     @Override
     protected void subscribeActual(MaybeObserver<? super T> observer) {
-        source.subscribe(new OnErrorCompleteMaybeObserver<>(observer, predicate));
+        source.subscribe(new OnErrorCompleteMultiObserver<>(observer, predicate));
     }
 
-    static final class OnErrorCompleteMaybeObserver<T> implements MaybeObserver<T>, Disposable {
+    public static final class OnErrorCompleteMultiObserver<T>
+    implements MaybeObserver<T>, SingleObserver<T>, Disposable {
 
         final MaybeObserver<? super T> downstream;
 
@@ -48,7 +49,7 @@ static final class OnErrorCompleteMaybeObserver<T> implements MaybeObserver<T>,
 
         Disposable upstream;
 
-        OnErrorCompleteMaybeObserver(MaybeObserver<? super T> actual, Predicate<? super Throwable> predicate) {
+        public OnErrorCompleteMultiObserver(MaybeObserver<? super T> actual, Predicate<? super Throwable> predicate) {
             this.downstream = actual;
             this.predicate = predicate;
         }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorComplete.java b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorComplete.java
new file mode 100644
index 0000000000..6854a5ce6d
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorComplete.java
@@ -0,0 +1,106 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.functions.Predicate;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+
+/**
+ * Emits an onComplete if the source emits an onError and the predicate returns true for
+ * that Throwable.
+ * 
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class ObservableOnErrorComplete<T> extends AbstractObservableWithUpstream<T, T> {
+
+    final Predicate<? super Throwable> predicate;
+
+    public ObservableOnErrorComplete(ObservableSource<T> source,
+            Predicate<? super Throwable> predicate) {
+        super(source);
+        this.predicate = predicate;
+    }
+
+    @Override
+    protected void subscribeActual(Observer<? super T> observer) {
+        source.subscribe(new OnErrorCompleteObserver<>(observer, predicate));
+    }
+
+    public static final class OnErrorCompleteObserver<T>
+    implements Observer<T>, Disposable {
+
+        final Observer<? super T> downstream;
+
+        final Predicate<? super Throwable> predicate;
+
+        Disposable upstream;
+
+        public OnErrorCompleteObserver(Observer<? super T> actual, Predicate<? super Throwable> predicate) {
+            this.downstream = actual;
+            this.predicate = predicate;
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onNext(T value) {
+            downstream.onNext(value);
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            boolean b;
+
+            try {
+                b = predicate.test(e);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                downstream.onError(new CompositeException(e, ex));
+                return;
+            }
+
+            if (b) {
+                downstream.onComplete();
+            } else {
+                downstream.onError(e);
+            }
+        }
+
+        @Override
+        public void onComplete() {
+            downstream.onComplete();
+        }
+
+        @Override
+        public void dispose() {
+            upstream.dispose();
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorComplete.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorComplete.java
new file mode 100644
index 0000000000..7be9bd817c
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorComplete.java
@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.Predicate;
+import io.reactivex.rxjava3.internal.operators.maybe.MaybeOnErrorComplete;
+
+/**
+ * Emits an onComplete if the source emits an onError and the predicate returns true for
+ * that Throwable.
+ * 
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class SingleOnErrorComplete<T> extends Maybe<T> {
+
+    final Single<T> source;
+
+    final Predicate<? super Throwable> predicate;
+
+    public SingleOnErrorComplete(Single<T> source,
+            Predicate<? super Throwable> predicate) {
+        this.source = source;
+        this.predicate = predicate;
+    }
+
+    @Override
+    protected void subscribeActual(MaybeObserver<? super T> observer) {
+        source.subscribe(new MaybeOnErrorComplete.OnErrorCompleteMultiObserver<T>(observer, predicate));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorCompleteTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorCompleteTest.java
new file mode 100644
index 0000000000..c1c89cbe27
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableOnErrorCompleteTest.java
@@ -0,0 +1,143 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Flowable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.processors.PublishProcessor;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class FlowableOnErrorCompleteTest {
+
+    @Test
+    public void normal() {
+        Flowable.range(1, 10)
+        .onErrorComplete()
+        .test()
+        .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+    }
+
+    @Test
+    public void normalBackpressured() {
+        Flowable.range(1, 10)
+        .onErrorComplete()
+        .test(0)
+        .assertEmpty()
+        .requestMore(3)
+        .assertValuesOnly(1, 2, 3)
+        .requestMore(3)
+        .assertValuesOnly(1, 2, 3, 4, 5, 6)
+        .requestMore(4)
+        .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+    }
+
+    @Test
+    public void empty() {
+        Flowable.empty()
+        .onErrorComplete()
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void error() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Flowable.error(new TestException())
+            .onErrorComplete()
+            .test()
+            .assertResult();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorMatches() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Flowable.error(new TestException())
+            .onErrorComplete(error -> error instanceof TestException)
+            .test()
+            .assertResult();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorNotMatches() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Flowable.error(new IOException())
+            .onErrorComplete(error -> error instanceof TestException)
+            .test()
+            .assertFailure(IOException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorPredicateCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            TestSubscriberEx<Object> ts = Flowable.error(new IOException())
+            .onErrorComplete(error -> { throw new TestException(); })
+            .subscribeWith(new TestSubscriberEx<>())
+            .assertFailure(CompositeException.class);
+
+            TestHelper.assertError(ts, 0, IOException.class);
+            TestHelper.assertError(ts, 1, TestException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void itemsThenError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Flowable.range(1, 5)
+            .map(v -> 4 / (3 - v))
+            .onErrorComplete()
+            .test()
+            .assertResult(2, 4);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void cancel() {
+        PublishProcessor<Integer> pp = PublishProcessor.create();
+
+        TestSubscriber<Integer> ts = pp
+                .onErrorComplete()
+                .test();
+
+        assertTrue("No subscribers?!", pp.hasSubscribers());
+
+        ts.cancel();
+
+        assertFalse("Still subscribers?!", pp.hasSubscribers());
+    }
+
+    @Test
+    public void onSubscribe() {
+        TestHelper.checkDoubleOnSubscribeFlowable(f -> f.onErrorComplete());
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorCompleteTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorCompleteTest.java
new file mode 100644
index 0000000000..4c37745834
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableOnErrorCompleteTest.java
@@ -0,0 +1,134 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Observable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.PublishSubject;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class ObservableOnErrorCompleteTest {
+
+    @Test
+    public void normal() {
+        Observable.range(1, 10)
+        .onErrorComplete()
+        .test()
+        .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+    }
+
+    @Test
+    public void empty() {
+        Observable.empty()
+        .onErrorComplete()
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void error() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Observable.error(new TestException())
+            .onErrorComplete()
+            .test()
+            .assertResult();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorMatches() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Observable.error(new TestException())
+            .onErrorComplete(error -> error instanceof TestException)
+            .test()
+            .assertResult();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorNotMatches() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Observable.error(new IOException())
+            .onErrorComplete(error -> error instanceof TestException)
+            .test()
+            .assertFailure(IOException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorPredicateCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            TestObserverEx<Object> to = Observable.error(new IOException())
+            .onErrorComplete(error -> { throw new TestException(); })
+            .subscribeWith(new TestObserverEx<>())
+            .assertFailure(CompositeException.class);
+
+            TestHelper.assertError(to, 0, IOException.class);
+            TestHelper.assertError(to, 1, TestException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void itemsThenError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Observable.range(1, 5)
+            .map(v -> 4 / (3 - v))
+            .onErrorComplete()
+            .test()
+            .assertResult(2, 4);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void dispose() {
+        PublishSubject<Integer> ps = PublishSubject.create();
+
+        TestObserver<Integer> to = ps
+                .onErrorComplete()
+                .test();
+
+        assertTrue("No subscribers?!", ps.hasObservers());
+
+        to.dispose();
+
+        assertFalse("Still subscribers?!", ps.hasObservers());
+    }
+
+    @Test
+    public void onSubscribe() {
+        TestHelper.checkDoubleOnSubscribeObservable(f -> f.onErrorComplete());
+    }
+
+    @Test
+    public void isDisposed() {
+        TestHelper.checkDisposed(PublishSubject.create().onErrorComplete());
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorCompleteTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorCompleteTest.java
new file mode 100644
index 0000000000..189759d6c6
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOnErrorCompleteTest.java
@@ -0,0 +1,113 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.*;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class SingleOnErrorCompleteTest {
+
+    @Test
+    public void normal() {
+        Single.just(1)
+        .onErrorComplete()
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void error() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new TestException())
+            .onErrorComplete()
+            .test()
+            .assertResult();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorMatches() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new TestException())
+            .onErrorComplete(error -> error instanceof TestException)
+            .test()
+            .assertResult();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorNotMatches() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new IOException())
+            .onErrorComplete(error -> error instanceof TestException)
+            .test()
+            .assertFailure(IOException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void errorPredicateCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            TestObserverEx<Object> to = Single.error(new IOException())
+            .onErrorComplete(error -> { throw new TestException(); })
+            .subscribeWith(new TestObserverEx<>())
+            .assertFailure(CompositeException.class);
+
+            TestHelper.assertError(to, 0, IOException.class);
+            TestHelper.assertError(to, 1, TestException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void dispose() {
+        SingleSubject<Integer> ss = SingleSubject.create();
+
+        TestObserver<Integer> to = ss
+                .onErrorComplete()
+                .test();
+
+        assertTrue("No subscribers?!", ss.hasObservers());
+
+        to.dispose();
+
+        assertFalse("Still subscribers?!", ss.hasObservers());
+    }
+
+    @Test
+    public void onSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingleToMaybe(f -> f.onErrorComplete());
+    }
+
+    @Test
+    public void isDisposed() {
+        TestHelper.checkDisposed(SingleSubject.create().onErrorComplete());
+    }
+}

From b157b8684d812fa58e14250f1570925539df096c Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 00:06:05 +0100
Subject: [PATCH 12/37] 3.x: Add Completable.onErrorResumeWith (#6868)

---
 .../reactivex/rxjava3/core/Completable.java   | 27 +++++++++++++++++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  4 +--
 .../CompletableResumeNextTest.java            | 29 +++++++++++++++++--
 3 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 0913ac398d..4a5bd55c39 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2086,6 +2086,33 @@ public final Completable onErrorResumeNext(@NonNull Function<? super Throwable,
         Objects.requireNonNull(fallbackSupplier, "fallbackSupplier is null");
         return RxJavaPlugins.onAssembly(new CompletableResumeNext(this, fallbackSupplier));
     }
+    /**
+     * Resumes the flow with the given {@link CompletableSource} when the current {@code Completable} fails instead of
+     * signaling the error via {@code onError}.
+     * <p>
+     * <img width="640" height="409" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.onErrorResumeWith.png" alt="">
+     * <p>
+     * You can use this to prevent errors from propagating or to supply fallback data should errors be
+     * encountered.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorResumeWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param fallback
+     *            the next {@code CompletableSource} that will take over if the current {@code Completable} encounters
+     *            an error
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code fallback} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Completable onErrorResumeWith(@NonNull CompletableSource fallback) {
+        Objects.requireNonNull(fallback, "fallback is null");
+        return onErrorResumeNext(Functions.justFunction(fallback));
+    }
 
     /**
      * Nulls out references to the upstream producer and downstream {@link CompletableObserver} if
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 1d385ce148..7bdfe05ee5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -4084,7 +4084,7 @@ public final Maybe<T> onErrorComplete(@NonNull Predicate<? super Throwable> pred
      * Resumes the flow with the given {@link MaybeSource} when the current {@code Maybe} fails instead of
      * signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onErrorResumeNext.png" alt="">
+     * <img width="640" height="298" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.onErrorResumeWith.png" alt="">
      * <p>
      * You can use this to prevent errors from propagating or to supply fallback data should errors be
      * encountered.
@@ -4112,7 +4112,7 @@ public final Maybe<T> onErrorResumeWith(@NonNull MaybeSource<? extends T> fallba
      * Resumes the flow with a {@link MaybeSource} returned for the failure {@link Throwable} of the current {@code Maybe} by a
      * function instead of signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onErrorResumeNext.png" alt="">
+     * <img width="640" height="298" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.onErrorResumeNext.png" alt="">
      * <p>
      * You can use this to prevent errors from propagating or to supply fallback data should errors be
      * encountered.
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableResumeNextTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableResumeNextTest.java
index 5670264378..fb5390cdcc 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableResumeNextTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableResumeNextTest.java
@@ -13,18 +13,19 @@
 
 package io.reactivex.rxjava3.internal.operators.completable;
 
+import static org.mockito.Mockito.*;
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
 import io.reactivex.rxjava3.exceptions.TestException;
-import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.functions.*;
 import io.reactivex.rxjava3.internal.functions.Functions;
 import io.reactivex.rxjava3.testsupport.TestHelper;
 
 public class CompletableResumeNextTest extends RxJavaTest {
 
     @Test
-    public void resumeWithError() {
+    public void resumeNextError() {
         Completable.error(new TestException())
         .onErrorResumeNext(Functions.justFunction(Completable.error(new TestException("second"))))
         .to(TestHelper.<Object>testConsumer())
@@ -58,4 +59,28 @@ public void disposed() {
                 .onErrorResumeNext(Functions.justFunction(Completable.never()))
         );
     }
+
+    @Test
+    public void resumeWithNoError() throws Throwable {
+        Action action = mock(Action.class);
+
+        Completable.complete()
+        .onErrorResumeWith(Completable.fromAction(action))
+        .test()
+        .assertResult();
+
+        verify(action, never()).run();
+    }
+
+    @Test
+    public void resumeWithError() throws Throwable {
+        Action action = mock(Action.class);
+
+        Completable.error(new TestException())
+        .onErrorResumeWith(Completable.fromAction(action))
+        .test()
+        .assertResult();
+
+        verify(action).run();
+    }
 }

From 320a675ec124cde872124d3bafd685e6a8998d0a Mon Sep 17 00:00:00 2001
From: akarnokd <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 00:08:49 +0100
Subject: [PATCH 13/37] Update Operator-Matrix generator and output

---
 docs/Operator-Matrix.md                       | 535 ++++++++++--------
 .../reactivex/rxjava3/core/Completable.java   |   1 +
 .../util/OperatorMatrixGenerator.java         |  30 +-
 3 files changed, 333 insertions(+), 233 deletions(-)

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 3c3ef2c765..1259584fea 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -17,7 +17,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='blockingNext'></a>`blockingNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
 <a name='blockingSingle'></a>`blockingSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
 <a name='blockingStream'></a>`blockingStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to get. Use blockingGet().'>([6](#notes-6))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No elements to get. Use blockingAwait().'>([7](#notes-7))</sup>|
-<a name='blockingSubscribe'></a>`blockingSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='blockingSubscribe'></a>`blockingSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='buffer'></a>`buffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a list/collection.'>([9](#notes-9))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a list/collection.'>([10](#notes-10))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a list/collection.'>([11](#notes-11))</sup>|
 <a name='cache'></a>`cache`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='cacheWithInitialCapacity'></a>`cacheWithInitialCapacity`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to store. Use cache().'>([12](#notes-12))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to store. Use cache().'>([12](#notes-12))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to store. Use cache().'>([12](#notes-12))</sup>|
@@ -32,211 +32,211 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='compose'></a>`compose`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concat'></a>`concat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concatArray'></a>`concatArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='concatArrayDelayError'></a>`concatArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatArrayDelayError'></a>`concatArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='concatArrayEager'></a>`concatArrayEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArray().'>([24](#notes-24))</sup>|
-<a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
-<a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
+<a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='concatEager'></a>`concatEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use merge().'>([26](#notes-26))</sup>|
-<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapCompletableDelayError'></a>`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapDelayError'></a>`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapCompletableDelayError'></a>`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapDelayError'></a>`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='concatWith'></a>`concatWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='contains'></a>`contains`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([31](#notes-31))</sup>|
+<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([34](#notes-34))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([35](#notes-35))</sup>|
 <a name='create'></a>`create`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
+<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
 <a name='defer'></a>`defer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delay'></a>`delay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delaySubscription'></a>`delaySubscription`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([37](#notes-37))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([41](#notes-41))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([41](#notes-41))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='doAfterTerminate'></a>`doAfterTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doFinally'></a>`doFinally`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([38](#notes-38))</sup>|
-<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([39](#notes-39))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([40](#notes-40))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([41](#notes-41))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([41](#notes-41))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|
+<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([43](#notes-43))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([44](#notes-44))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='doOnError'></a>`doOnError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([42](#notes-42))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
+<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([46](#notes-46))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
 <a name='doOnSubscribe'></a>`doOnSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([45](#notes-45))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([49](#notes-49))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([49](#notes-49))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='doOnTerminate'></a>`doOnTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([49](#notes-49))</sup>|
+<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([53](#notes-53))</sup>|
 <a name='error'></a>`error`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
-<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([54](#notes-54))</sup>|
-<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([56](#notes-56))</sup>|
-<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|
+<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
+<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([58](#notes-58))</sup>|
+<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([60](#notes-60))</sup>|
+<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|
 <a name='flatMap'></a>`flatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='flatMapCompletable'></a>`flatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([58](#notes-58))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([59](#notes-59))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapSingleElement'></a>`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([60](#notes-60))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([61](#notes-61))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([62](#notes-62))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|
-<a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([63](#notes-63))</sup>|
-<a name='fromAction'></a>`fromAction`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromArray'></a>`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([61](#notes-61))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([63](#notes-63))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([64](#notes-64))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapSingleElement'></a>`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([65](#notes-65))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|
+<a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|
+<a name='fromAction'></a>`fromAction`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromArray'></a>`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
 <a name='fromCallable'></a>`fromCallable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromCompletable'></a>`fromCompletable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([68](#notes-68))</sup>|
+<a name='fromCompletable'></a>`fromCompletable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|
 <a name='fromCompletionStage'></a>`fromCompletionStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromFuture'></a>`fromFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromIterable'></a>`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
-<a name='fromMaybe'></a>`fromMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromObservable'></a>`fromObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromOptional'></a>`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
-<a name='fromPublisher'></a>`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromRunnable'></a>`fromRunnable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromSingle'></a>`fromSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromStream'></a>`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
+<a name='fromIterable'></a>`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='fromMaybe'></a>`fromMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromObservable'></a>`fromObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromOptional'></a>`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='fromPublisher'></a>`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromRunnable'></a>`fromRunnable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromSingle'></a>`fromSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromStream'></a>`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
 <a name='fromSupplier'></a>`fromSupplier`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='generate'></a>`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([69](#notes-69))</sup>|
-<a name='groupBy'></a>`groupBy`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to group.'>([71](#notes-71))</sup>|
-<a name='groupJoin'></a>`groupJoin`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([72](#notes-72))</sup>|
+<a name='generate'></a>`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|
+<a name='groupBy'></a>`groupBy`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to group.'>([76](#notes-76))</sup>|
+<a name='groupJoin'></a>`groupJoin`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([77](#notes-77))</sup>|
 <a name='hide'></a>`hide`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='ignoreElement'></a>`ignoreElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='ignoreElements'></a>`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='interval'></a>`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|
-<a name='intervalRange'></a>`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([75](#notes-75))</sup>|
-<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='join'></a>`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([76](#notes-76))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([76](#notes-76))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([72](#notes-72))</sup>|
-<a name='just'></a>`just`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
-<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([54](#notes-54))</sup>|
-<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([56](#notes-56))</sup>|
-<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|
+<a name='ignoreElement'></a>`ignoreElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([78](#notes-78))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='ignoreElements'></a>`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='interval'></a>`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|
+<a name='intervalRange'></a>`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|
+<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='join'></a>`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([81](#notes-81))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([81](#notes-81))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([77](#notes-77))</sup>|
+<a name='just'></a>`just`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
+<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([58](#notes-58))</sup>|
+<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([60](#notes-60))</sup>|
+<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|
 <a name='lift'></a>`lift`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='map'></a>`map`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='mapOptional'></a>`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='materialize'></a>`materialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='merge'></a>`merge`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='mergeArray'></a>`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='mergeArrayDelayError'></a>`mergeArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeArray'></a>`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeArrayDelayError'></a>`mergeArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='mergeDelayError'></a>`mergeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='mergeWith'></a>`mergeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='never'></a>`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='observeOn'></a>`observeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([77](#notes-77))</sup>|
-<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
-<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
-<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
-<a name='onErrorComplete'></a>`onErrorComplete`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([82](#notes-82))</sup>|
+<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
+<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
+<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
+<a name='onErrorComplete'></a>`onErrorComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeNext'></a>`onErrorResumeNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='onErrorResumeWith'></a>`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='onErrorReturn'></a>`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='onErrorReturnItem'></a>`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='onErrorResumeWith'></a>`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='onErrorReturn'></a>`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='onErrorReturnItem'></a>`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='onTerminateDetach'></a>`onTerminateDetach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='parallel'></a>`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([78](#notes-78))</sup>|
-<a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
-<a name='range'></a>`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
-<a name='rangeLong'></a>`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([66](#notes-66))</sup>|
-<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([44](#notes-44))</sup>|
-<a name='reduce'></a>`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
-<a name='reduceWith'></a>`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
+<a name='parallel'></a>`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|
+<a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
+<a name='range'></a>`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='rangeLong'></a>`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
+<a name='reduce'></a>`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
+<a name='reduceWith'></a>`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
 <a name='repeat'></a>`repeat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='repeatUntil'></a>`repeatUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='repeatWhen'></a>`repeatWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='replay'></a>`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
+<a name='replay'></a>`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
 <a name='retry'></a>`retry`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='retryWhen'></a>`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
-<a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([84](#notes-84))</sup>|
-<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([85](#notes-85))</sup>|
-<a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([81](#notes-81))</sup>|
-<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([34](#notes-34))</sup>|
-<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([54](#notes-54))</sup>|
-<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([56](#notes-56))</sup>|
-<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([55](#notes-55))</sup>|
-<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
-<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
-<a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([86](#notes-86))</sup>|
-<a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([70](#notes-70))</sup>|
-<a name='startWith'></a>`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='startWithArray'></a>`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([88](#notes-88))</sup>|
-<a name='startWithItem'></a>`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([89](#notes-89))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([89](#notes-89))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([89](#notes-89))</sup>|
-<a name='startWithIterable'></a>`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([90](#notes-90))</sup>|
+<a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
+<a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
+<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([90](#notes-90))</sup>|
+<a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
+<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
+<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([58](#notes-58))</sup>|
+<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([60](#notes-60))</sup>|
+<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|
+<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
+<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
+<a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([91](#notes-91))</sup>|
+<a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|
+<a name='startWith'></a>`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='startWithArray'></a>`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([93](#notes-93))</sup>|
+<a name='startWithItem'></a>`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([94](#notes-94))</sup>|
+<a name='startWithIterable'></a>`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([95](#notes-95))</sup>|
 <a name='subscribe'></a>`subscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='subscribeOn'></a>`subscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='subscribeWith'></a>`subscribeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='switchIfEmpty'></a>`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use defaultIfEmpty().'>([91](#notes-91))</sup>|
-<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
-<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
-<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([52](#notes-52))</sup>|
+<a name='switchIfEmpty'></a>`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use defaultIfEmpty().'>([96](#notes-96))</sup>|
+<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
+<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
 <a name='takeUntil'></a>`takeUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='takeWhile'></a>`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='takeWhile'></a>`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='test'></a>`test`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
-<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='timeout'></a>`timeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='timer'></a>`timer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([33](#notes-33))</sup>|
+<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([93](#notes-93))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)|
+<a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='toList'></a>`toList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='toMap'></a>`toMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
-<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toMultimap'></a>`toMultimap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
-<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([96](#notes-96))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([94](#notes-94))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([101](#notes-101))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([101](#notes-101))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([102](#notes-102))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([102](#notes-102))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([103](#notes-103))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toSortedList'></a>`toSortedList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='unsafeCreate'></a>`unsafeCreate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='unsubscribeOn'></a>`unsubscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='using'></a>`using`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='window'></a>`window`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([99](#notes-99))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a nested source.'>([101](#notes-101))</sup>|
+<a name='window'></a>`window`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([104](#notes-104))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([105](#notes-105))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a nested source.'>([106](#notes-106))</sup>|
 <a name='withLatestFrom'></a>`withLatestFrom`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use merge().'>([17](#notes-17))</sup>|
-<a name='wrap'></a>`wrap`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromPublisher().'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([103](#notes-103))</sup>|
-<a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([104](#notes-104))</sup>|
-<a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([105](#notes-105))</sup>|
+<a name='wrap'></a>`wrap`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromPublisher().'>([107](#notes-107))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([108](#notes-108))</sup>|
+<a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([109](#notes-109))</sup>|
+<a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([110](#notes-110))</sup>|
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -266,81 +266,154 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='notes-25'></a><sup>25</sup> No items to keep ordered. Use [`mergeArrayDelayError()`](#mergeArrayDelayError).<br/>
 <a name='notes-26'></a><sup>26</sup> No items to keep ordered. Use [`merge()`](#merge).<br/>
 <a name='notes-27'></a><sup>27</sup> Always empty thus no items to map.<br/>
-<a name='notes-28'></a><sup>28</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
-<a name='notes-29'></a><sup>29</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
-<a name='notes-30'></a><sup>30</sup> Never empty thus always 1.<br/>
-<a name='notes-31'></a><sup>31</sup> Always empty thus always 0.<br/>
-<a name='notes-32'></a><sup>32</sup> At most one item signaled so no subsequent items to work with.<br/>
-<a name='notes-33'></a><sup>33</sup> Always empty thus no items to work with.<br/>
-<a name='notes-34'></a><sup>34</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
-<a name='notes-35'></a><sup>35</sup> At most one item, always distinct.<br/>
-<a name='notes-36'></a><sup>36</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
-<a name='notes-37'></a><sup>37</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
-<a name='notes-38'></a><sup>38</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
-<a name='notes-39'></a><sup>39</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
-<a name='notes-40'></a><sup>40</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
-<a name='notes-41'></a><sup>41</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
-<a name='notes-42'></a><sup>42</sup> Use [`doOnEach()`](#doOnEach).<br/>
-<a name='notes-43'></a><sup>43</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
-<a name='notes-44'></a><sup>44</sup> Backpressure related and not supported outside `Flowable`.<br/>
-<a name='notes-45'></a><sup>45</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
-<a name='notes-46'></a><sup>46</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
-<a name='notes-47'></a><sup>47</sup> Always one item with index 0.<br/>
-<a name='notes-48'></a><sup>48</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
-<a name='notes-49'></a><sup>49</sup> Use [`complete()`](#complete).<br/>
-<a name='notes-50'></a><sup>50</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
-<a name='notes-51'></a><sup>51</sup> Always one item.<br/>
-<a name='notes-52'></a><sup>52</sup> At most one item, would be no-op.<br/>
-<a name='notes-53'></a><sup>53</sup> Always one item, would be no-op.<br/>
-<a name='notes-54'></a><sup>54</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
-<a name='notes-55'></a><sup>55</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
-<a name='notes-56'></a><sup>56</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
-<a name='notes-57'></a><sup>57</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
-<a name='notes-58'></a><sup>58</sup> Use [`flatMap`](#flatMap).<br/>
-<a name='notes-59'></a><sup>59</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
-<a name='notes-60'></a><sup>60</sup> Use [`flatMapSingle`](#flatMapSingle).<br/>
-<a name='notes-61'></a><sup>61</sup> Use [`flatMapIterable()`](#flatMapIterable).<br/>
-<a name='notes-62'></a><sup>62</sup> Use [`flatMapStream()`](#flatMapStream).<br/>
-<a name='notes-63'></a><sup>63</sup> Use [`subscribe()`](#subscribe).<br/>
-<a name='notes-64'></a><sup>64</sup> At most one item. Use [`just()`](#just) or [`empty()`](#empty).<br/>
-<a name='notes-65'></a><sup>65</sup> Always one item. Use [`just()`](#just).<br/>
-<a name='notes-66'></a><sup>66</sup> Always empty. Use [`complete()`](#complete).<br/>
-<a name='notes-67'></a><sup>67</sup> Always error.<br/>
-<a name='notes-68'></a><sup>68</sup> Use [`wrap()`](#wrap).<br/>
-<a name='notes-69'></a><sup>69</sup> Use [`fromSupplier()`](#fromSupplier).<br/>
-<a name='notes-70'></a><sup>70</sup> At most one item.<br/>
-<a name='notes-71'></a><sup>71</sup> Always empty thus no items to group.<br/>
-<a name='notes-72'></a><sup>72</sup> Always empty thus no items to join.<br/>
-<a name='notes-73'></a><sup>73</sup> Use [`ignoreElements()`](#ignoreElements).<br/>
-<a name='notes-74'></a><sup>74</sup> Use [`ignoreElement()`](#ignoreElement).<br/>
-<a name='notes-75'></a><sup>75</sup> At most one item. Use [`timer()`](#timer).<br/>
-<a name='notes-76'></a><sup>76</sup> At most one item. Use [`zip()`](#zip)<br/>
-<a name='notes-77'></a><sup>77</sup> Always empty thus no items to filter.<br/>
-<a name='notes-78'></a><sup>78</sup> Needs backpressure thus not supported outside `Flowable`.<br/>
-<a name='notes-79'></a><sup>79</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.<br/>
-<a name='notes-80'></a><sup>80</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.<br/>
-<a name='notes-81'></a><sup>81</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.<br/>
-<a name='notes-82'></a><sup>82</sup> At most one item. Use [`just()`](#just).<br/>
-<a name='notes-83'></a><sup>83</sup> At most one item. Use [`map()`](#map).<br/>
-<a name='notes-84'></a><sup>84</sup> Always empty thus no items to reduce.<br/>
-<a name='notes-85'></a><sup>85</sup> At most one signal type.<br/>
-<a name='notes-86'></a><sup>86</sup> At most one item. Use [`takeUntil()`](#takeUntil).<br/>
-<a name='notes-87'></a><sup>87</sup> At most one item. Use [`filter()`](#filter).<br/>
-<a name='notes-88'></a><sup>88</sup> Use [`startWith()`](#startWith) and [`fromArray()`](#fromArray) of `Flowable` or `Observable`.<br/>
-<a name='notes-89'></a><sup>89</sup> Use [`startWith()`](#startWith) and [`just()`](#just) of another reactive type.<br/>
-<a name='notes-90'></a><sup>90</sup> Use [`startWith()`](#startWith) and [`fromIterable()`](#fromArray) of `Flowable` or `Observable`.<br/>
-<a name='notes-91'></a><sup>91</sup> Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
-<a name='notes-92'></a><sup>92</sup> At most one item. Use [`flatMap()`](#flatMap).<br/>
-<a name='notes-93'></a><sup>93</sup> Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).<br/>
-<a name='notes-94'></a><sup>94</sup> Would be no-op.<br/>
-<a name='notes-95'></a><sup>95</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
-<a name='notes-96'></a><sup>96</sup> Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).<br/>
-<a name='notes-97'></a><sup>97</sup> Use [`first`](#first), [`last`](#last) or [`single`](#single).<br/>
-<a name='notes-98'></a><sup>98</sup> Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
-<a name='notes-99'></a><sup>99</sup> Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a nested source.<br/>
-<a name='notes-100'></a><sup>100</sup> Use [`map()`](#map) to transform into a nested source.<br/>
-<a name='notes-101'></a><sup>101</sup> Always empty. Use [`andThen()`](#andThen) to bring in a nested source.<br/>
-<a name='notes-102'></a><sup>102</sup> Use [`fromPublisher()`](#fromPublisher).<br/>
-<a name='notes-103'></a><sup>103</sup> Use [`merge()`](#merge).<br/>
-<a name='notes-104'></a><sup>104</sup> Use [`mergeArray()`](#mergeArray).<br/>
-<a name='notes-105'></a><sup>105</sup> Use [`mergeWith()`](#mergeWith).<br/>
+<a name='notes-28'></a><sup>28</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use [`concatMapCompletable`](#concatMapCompletable).<br/>
+<a name='notes-29'></a><sup>29</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMap`](#concatMap).<br/>
+<a name='notes-30'></a><sup>30</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
+<a name='notes-31'></a><sup>31</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).<br/>
+<a name='notes-32'></a><sup>32</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).<br/>
+<a name='notes-33'></a><sup>33</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
+<a name='notes-34'></a><sup>34</sup> Never empty thus always 1.<br/>
+<a name='notes-35'></a><sup>35</sup> Always empty thus always 0.<br/>
+<a name='notes-36'></a><sup>36</sup> At most one item signaled so no subsequent items to work with.<br/>
+<a name='notes-37'></a><sup>37</sup> Always empty thus no items to work with.<br/>
+<a name='notes-38'></a><sup>38</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
+<a name='notes-39'></a><sup>39</sup> At most one item, always distinct.<br/>
+<a name='notes-40'></a><sup>40</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
+<a name='notes-41'></a><sup>41</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
+<a name='notes-42'></a><sup>42</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
+<a name='notes-43'></a><sup>43</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
+<a name='notes-44'></a><sup>44</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
+<a name='notes-45'></a><sup>45</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
+<a name='notes-46'></a><sup>46</sup> Use [`doOnEach()`](#doOnEach).<br/>
+<a name='notes-47'></a><sup>47</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
+<a name='notes-48'></a><sup>48</sup> Backpressure related and not supported outside `Flowable`.<br/>
+<a name='notes-49'></a><sup>49</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
+<a name='notes-50'></a><sup>50</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-51'></a><sup>51</sup> Always one item with index 0.<br/>
+<a name='notes-52'></a><sup>52</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
+<a name='notes-53'></a><sup>53</sup> Use [`complete()`](#complete).<br/>
+<a name='notes-54'></a><sup>54</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-55'></a><sup>55</sup> Always one item.<br/>
+<a name='notes-56'></a><sup>56</sup> At most one item, would be no-op.<br/>
+<a name='notes-57'></a><sup>57</sup> Always one item, would be no-op.<br/>
+<a name='notes-58'></a><sup>58</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
+<a name='notes-59'></a><sup>59</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-60'></a><sup>60</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-61'></a><sup>61</sup> Use [`flatMap()`](#flatMap).<br/>
+<a name='notes-62'></a><sup>62</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
+<a name='notes-63'></a><sup>63</sup> Use [`flatMap`](#flatMap).<br/>
+<a name='notes-64'></a><sup>64</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
+<a name='notes-65'></a><sup>65</sup> Use [`flatMapSingle`](#flatMapSingle).<br/>
+<a name='notes-66'></a><sup>66</sup> Use [`flatMapIterable()`](#flatMapIterable).<br/>
+<a name='notes-67'></a><sup>67</sup> Use [`flatMapStream()`](#flatMapStream).<br/>
+<a name='notes-68'></a><sup>68</sup> Use [`subscribe()`](#subscribe).<br/>
+<a name='notes-69'></a><sup>69</sup> At most one item. Use [`just()`](#just) or [`empty()`](#empty).<br/>
+<a name='notes-70'></a><sup>70</sup> Always one item. Use [`just()`](#just).<br/>
+<a name='notes-71'></a><sup>71</sup> Always empty. Use [`complete()`](#complete).<br/>
+<a name='notes-72'></a><sup>72</sup> Always error.<br/>
+<a name='notes-73'></a><sup>73</sup> Use [`wrap()`](#wrap).<br/>
+<a name='notes-74'></a><sup>74</sup> Use [`fromSupplier()`](#fromSupplier).<br/>
+<a name='notes-75'></a><sup>75</sup> At most one item.<br/>
+<a name='notes-76'></a><sup>76</sup> Always empty thus no items to group.<br/>
+<a name='notes-77'></a><sup>77</sup> Always empty thus no items to join.<br/>
+<a name='notes-78'></a><sup>78</sup> Use [`ignoreElements()`](#ignoreElements).<br/>
+<a name='notes-79'></a><sup>79</sup> Use [`ignoreElement()`](#ignoreElement).<br/>
+<a name='notes-80'></a><sup>80</sup> At most one item. Use [`timer()`](#timer).<br/>
+<a name='notes-81'></a><sup>81</sup> At most one item. Use [`zip()`](#zip)<br/>
+<a name='notes-82'></a><sup>82</sup> Always empty thus no items to filter.<br/>
+<a name='notes-83'></a><sup>83</sup> Needs backpressure thus not supported outside `Flowable`.<br/>
+<a name='notes-84'></a><sup>84</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.<br/>
+<a name='notes-85'></a><sup>85</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.<br/>
+<a name='notes-86'></a><sup>86</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.<br/>
+<a name='notes-87'></a><sup>87</sup> At most one item. Use [`just()`](#just).<br/>
+<a name='notes-88'></a><sup>88</sup> At most one item. Use [`map()`](#map).<br/>
+<a name='notes-89'></a><sup>89</sup> Always empty thus no items to reduce.<br/>
+<a name='notes-90'></a><sup>90</sup> At most one signal type.<br/>
+<a name='notes-91'></a><sup>91</sup> At most one item. Use [`takeUntil()`](#takeUntil).<br/>
+<a name='notes-92'></a><sup>92</sup> At most one item. Use [`filter()`](#filter).<br/>
+<a name='notes-93'></a><sup>93</sup> Use [`startWith()`](#startWith) and [`fromArray()`](#fromArray) of `Flowable` or `Observable`.<br/>
+<a name='notes-94'></a><sup>94</sup> Use [`startWith()`](#startWith) and [`just()`](#just) of another reactive type.<br/>
+<a name='notes-95'></a><sup>95</sup> Use [`startWith()`](#startWith) and [`fromIterable()`](#fromArray) of `Flowable` or `Observable`.<br/>
+<a name='notes-96'></a><sup>96</sup> Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
+<a name='notes-97'></a><sup>97</sup> At most one item. Use [`flatMap()`](#flatMap).<br/>
+<a name='notes-98'></a><sup>98</sup> Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).<br/>
+<a name='notes-99'></a><sup>99</sup> Would be no-op.<br/>
+<a name='notes-100'></a><sup>100</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
+<a name='notes-101'></a><sup>101</sup> Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).<br/>
+<a name='notes-102'></a><sup>102</sup> Use [`first`](#first), [`last`](#last) or [`single`](#single).<br/>
+<a name='notes-103'></a><sup>103</sup> Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
+<a name='notes-104'></a><sup>104</sup> Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a nested source.<br/>
+<a name='notes-105'></a><sup>105</sup> Use [`map()`](#map) to transform into a nested source.<br/>
+<a name='notes-106'></a><sup>106</sup> Always empty. Use [`andThen()`](#andThen) to bring in a nested source.<br/>
+<a name='notes-107'></a><sup>107</sup> Use [`fromPublisher()`](#fromPublisher).<br/>
+<a name='notes-108'></a><sup>108</sup> Use [`merge()`](#merge).<br/>
+<a name='notes-109'></a><sup>109</sup> Use [`mergeArray()`](#mergeArray).<br/>
+<a name='notes-110'></a><sup>110</sup> Use [`mergeWith()`](#mergeWith).<br/>
+
+#### Under development
+
+1. Single.concatArrayDelayError()
+2. Completable.concatArrayDelayError()
+3. Maybe.concatArrayEagerDelayError()
+4. Single.concatArrayEagerDelayError()
+5. Single.concatDelayError()
+6. Completable.concatDelayError()
+7. Single.concatMap()
+8. Maybe.concatMapCompletable()
+9. Single.concatMapCompletable()
+10. Maybe.concatMapEager()
+11. Single.concatMapEager()
+12. Completable.concatMapEager()
+13. Maybe.concatMapEagerDelayError()
+14. Single.concatMapEagerDelayError()
+15. Completable.concatMapEagerDelayError()
+16. Maybe.concatMapMaybe()
+17. Single.concatMapMaybe()
+18. Maybe.concatMapSingle()
+19. Single.concatMapSingle()
+20. Maybe.dematerialize()
+21. Maybe.doOnLifecycle()
+22. Single.doOnLifecycle()
+23. Completable.doOnLifecycle()
+24. Flowable.fromAction()
+25. Observable.fromAction()
+26. Single.fromAction()
+27. Flowable.fromCompletable()
+28. Observable.fromCompletable()
+29. Flowable.fromMaybe()
+30. Observable.fromMaybe()
+31. Single.fromMaybe()
+32. Flowable.fromObservable()
+33. Maybe.fromObservable()
+34. Maybe.fromPublisher()
+35. Flowable.fromRunnable()
+36. Observable.fromRunnable()
+37. Single.fromRunnable()
+38. Flowable.fromSingle()
+39. Observable.fromSingle()
+40. Single.mergeArray()
+41. Single.mergeArrayDelayError()
+42. Single.ofType()
+43. Completable.onErrorReturn()
+44. Completable.onErrorReturnItem()
+45. Single.retryUntil()
+46. Completable.retryUntil()
+47. Maybe.safeSubscribe()
+48. Single.safeSubscribe()
+49. Completable.safeSubscribe()
+50. Completable.sequenceEqual()
+51. Maybe.startWith()
+52. Single.startWith()
+53. Maybe.switchOnNext()
+54. Single.switchOnNext()
+55. Completable.switchOnNext()
+56. Maybe.switchOnNextDelayError()
+57. Single.switchOnNextDelayError()
+58. Completable.switchOnNextDelayError()
+59. Maybe.timeInterval()
+60. Single.timeInterval()
+61. Completable.timeInterval()
+62. Maybe.timestamp()
+63. Single.timestamp()
+64. Maybe.toFuture()
+65. Completable.toFuture()
diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 4a5bd55c39..f0b1f2bea0 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2105,6 +2105,7 @@ public final Completable onErrorResumeNext(@NonNull Function<? super Throwable,
      * @return the new {@code Completable} instance
      * @throws NullPointerException if {@code fallback} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
+     * @since 3.0.0
      */
     @CheckReturnValue
     @NonNull
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index 970d6e36bb..d99202adef 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -35,6 +35,7 @@ private OperatorMatrixGenerator() {
 
     static final String PRESENT = "![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)";
     static final String ABSENT = "![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png)";
+    static final String TBD = "![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)";
 
     static final Class<?>[] CLASSES = {
             Flowable.class, Observable.class, Maybe.class, Single.class, Completable.class
@@ -81,6 +82,7 @@ public static void main(String[] args) throws IOException {
 
             Map<String, Integer> notesMap = new HashMap<>();
             List<String> notesList = new ArrayList<>();
+            List<String> tbdList = new ArrayList<>();
 
             for (String operatorName : sortedOperators) {
                 out.print("<a name='");
@@ -92,9 +94,9 @@ public static void main(String[] args) throws IOException {
                     if (operatorMap.get(clazz).contains(operatorName)) {
                         out.print(PRESENT);
                     } else {
-                        out.print(ABSENT);
                         String notes = findNotes(clazz.getSimpleName(), operatorName);
                         if (notes != null) {
+                            out.print(ABSENT);
                             Integer index = notesMap.get(notes);
                             if (index == null) {
                                 index = notesMap.size() + 1;
@@ -108,6 +110,9 @@ public static void main(String[] args) throws IOException {
                             out.print("](#notes-");
                             out.print(index);
                             out.print("))</sup>");
+                        } else {
+                            out.print(TBD);
+                            tbdList.add(clazz.getSimpleName() + "." + operatorName + "()");
                         }
                     }
                     out.print("|");
@@ -129,6 +134,17 @@ public static void main(String[] args) throws IOException {
                     out.println("<br/>");
                 }
             }
+            if (!tbdList.isEmpty()) {
+                out.println();
+                out.println("#### Under development");
+                out.println();
+
+                for (int i = 0; i < tbdList.size(); i++) {
+                    out.print(i + 1);
+                    out.print(". ");
+                    out.println(tbdList.get(i));
+                }
+            }
         }
     }
 
@@ -207,11 +223,16 @@ static String findNotes(String clazzName, String operatorName) {
             "    C concatEagerDelayError                No items to keep ordered. Use [`mergeDelayError()`](#mergeDelayError).",
             "    C concatMap                            Always empty thus no items to map.",
             "    C concatMapCompletable                 Always empty thus no items to map.",
+            "  MS  concatMapCompletableDelayError       Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use [`concatMapCompletable`](#concatMapCompletable).",
             "    C concatMapCompletableDelayError       Always empty thus no items to map.",
+            "  MS  concatMapDelayError                  Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMap`](#concatMap).",
+            "    C concatMapDelayError                  Always empty thus no items to map.",
             "    C concatMapIterable                    Always empty thus no items to map.",
             "    C concatMapMaybe                       Always empty thus no items to map.",
+            "  MS  concatMapMaybeDelayError             Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).",
             "    C concatMapMaybeDelayError             Always empty thus no items to map.",
             "    C concatMapSingle                      Always empty thus no items to map.",
+            "  MS  concatMapSingleDelayError            Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).",
             "    C concatMapSingleDelayError            Always empty thus no items to map.",
             "    C concatMapStream                      Always empty thus no items to map.",
             "  MS  concatMapIterable                    At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).",
@@ -247,6 +268,8 @@ static String findNotes(String clazzName, String operatorName) {
             "   S  elementAt                            Always one item with index 0.",
             "    C elementAt                            Always empty thus no items to work with.",
             "  M   elementAtOrError                     At most one item with index 0. Use [`toSingle`](#toSingle).",
+            "   S  elementAtOrError                     Always one item with index 0.",
+            "    C elementAtOrError                     Always empty thus no items to work with.",
             "   S  empty                                Never empty.",
             "    C empty                                Use [`complete()`](#complete).",
             "    C filter                               Always empty thus no items to work with.",
@@ -266,10 +289,11 @@ static String findNotes(String clazzName, String operatorName) {
             "    C flatMapCompletable                   Always empty thus no items to map.",
             "    C flatMapCompletableDelayError         Always empty thus no items to map.",
             "    C flatMapIterable                      Always empty thus no items to map.",
+            "  M   flatMapMaybe                         Use [`flatMap()`](#flatMap).",
             "    C flatMapMaybe                         Always empty thus no items to map.",
             "    C flatMapMaybeDelayError               Always empty thus no items to map.",
+            "   S  flatMapSingle                        Use [`flatMap()`](#flatMap).",
             "    C flatMapSingle                        Always empty thus no items to map.",
-            "    C flatMapSingleDelayError              Always empty thus no items to map.",
             "    C flatMapStream                        Always empty thus no items to map.",
             "  MS  flatMapIterable                      At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).",
             "  MS  flatMapStream                        At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).",
@@ -304,6 +328,7 @@ static String findNotes(String clazzName, String operatorName) {
             " O    fromObservable                       Use [`wrap()`](#wrap).",
             "   S  fromOptional                         Always one item. Use [`just()`](#just).",
             "    C fromOptional                         Always empty. Use [`complete()`](#complete).",
+            "   S  fromSingle                           Use [`wrap()`](#wrap).",
             "  M   fromStream                           At most one item. Use [`just()`](#just) or [`empty()`](#empty).",
             "   S  fromStream                           Always one item. Use [`just()`](#just).",
             "    C fromStream                           Always empty. Use [`complete()`](#complete).",
@@ -322,6 +347,7 @@ static String findNotes(String clazzName, String operatorName) {
             "    C isEmpty                              Always empty.",
             "  MS  join                                 At most one item. Use [`zip()`](#zip)",
             "    C join                                 Always empty thus no items to join.",
+            "    C just                                 Always empty.",
             "  M   last                                 At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).",
             "   S  last                                 Always one item.",
             "    C last                                 Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.",

From 0ed3572c8961dfdfa7dc73dd0419b5f789d1d1ad Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 10:56:11 +0100
Subject: [PATCH 14/37] 3.x: Add S/C retryUntil + marbles (#6869)

---
 .../reactivex/rxjava3/core/Completable.java   | 20 +++++++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  2 +
 .../io/reactivex/rxjava3/core/Single.java     | 20 +++++++
 .../completable/CompletableRetryTest.java     | 39 +++++++++++++
 .../rxjava3/maybe/MaybeRetryTest.java         | 55 +++++++++++++++++++
 .../rxjava3/single/SingleRetryTest.java       | 39 +++++++++++++
 6 files changed, 175 insertions(+)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index f0b1f2bea0..81028f726e 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2317,6 +2317,26 @@ public final Completable retry(@NonNull Predicate<? super Throwable> predicate)
         return fromPublisher(toFlowable().retry(predicate));
     }
 
+    /**
+     * Retries until the given stop function returns {@code true}.
+     * <p>
+     * <img width="640" height="354" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.retryUntil.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param stop the function that should return {@code true} to stop retrying
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code stop} is {@code null}
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Completable retryUntil(@NonNull BooleanSupplier stop) {
+        Objects.requireNonNull(stop, "stop is null");
+        return retry(Long.MAX_VALUE, Functions.predicateReverseFor(stop));
+    }
+
     /**
      * Returns a {@code Completable} which given a {@link Publisher} and when this {@code Completable} emits an error, delivers
      * that error through a {@link Flowable} and the {@code Publisher} should signal a value indicating a retry in response
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 7bdfe05ee5..98065a40d5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -4433,6 +4433,8 @@ public final Maybe<T> retry(@NonNull Predicate<? super Throwable> predicate) {
 
     /**
      * Retries until the given stop function returns {@code true}.
+     * <p>
+     * <img width="640" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retryUntil.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index f6e41cee5c..e17ff9e8ec 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -3747,6 +3747,26 @@ public final Single<T> retry(@NonNull Predicate<? super Throwable> predicate) {
         return toSingle(toFlowable().retry(predicate));
     }
 
+    /**
+     * Retries until the given stop function returns {@code true}.
+     * <p>
+     * <img width="640" height="364" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.retryUntil.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param stop the function that should return {@code true} to stop retrying
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code stop} is {@code null}
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Single<T> retryUntil(@NonNull BooleanSupplier stop) {
+        Objects.requireNonNull(stop, "stop is null");
+        return retry(Long.MAX_VALUE, Functions.predicateReverseFor(stop));
+    }
+
     /**
      * Re-subscribes to the current {@code Single} if and when the {@link Publisher} returned by the handler
      * function signals a value.
diff --git a/src/test/java/io/reactivex/rxjava3/completable/CompletableRetryTest.java b/src/test/java/io/reactivex/rxjava3/completable/CompletableRetryTest.java
index 909ce35669..c805f68c6f 100644
--- a/src/test/java/io/reactivex/rxjava3/completable/CompletableRetryTest.java
+++ b/src/test/java/io/reactivex/rxjava3/completable/CompletableRetryTest.java
@@ -20,6 +20,7 @@
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.*;
 import io.reactivex.rxjava3.internal.functions.Functions;
 
@@ -113,4 +114,42 @@ public void retryTimesPredicateWithZeroRetries() {
 
         assertEquals(1, numberOfSubscribeCalls.get());
     }
+
+    @Test
+    public void untilTrueEmpty() {
+        Completable.complete()
+        .retryUntil(() -> true)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilFalseEmpty() {
+        Completable.complete()
+        .retryUntil(() -> false)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilTrueError() {
+        Completable.error(new TestException())
+        .retryUntil(() -> true)
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void untilFalseError() {
+        AtomicInteger counter = new AtomicInteger();
+        Completable.defer(() -> {
+            if (counter.getAndIncrement() == 0) {
+                return Completable.error(new TestException());
+            }
+            return Completable.complete();
+        })
+        .retryUntil(() -> false)
+        .test()
+        .assertResult();
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/maybe/MaybeRetryTest.java b/src/test/java/io/reactivex/rxjava3/maybe/MaybeRetryTest.java
index f260a78a82..6c88f8501c 100644
--- a/src/test/java/io/reactivex/rxjava3/maybe/MaybeRetryTest.java
+++ b/src/test/java/io/reactivex/rxjava3/maybe/MaybeRetryTest.java
@@ -21,6 +21,7 @@
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.Predicate;
 import io.reactivex.rxjava3.internal.functions.Functions;
 
@@ -120,4 +121,58 @@ public void retryTimesPredicateWithZeroRetries() {
 
         assertEquals(1, numberOfSubscribeCalls.get());
     }
+
+    @Test
+    public void untilTrueJust() {
+        Maybe.just(1)
+        .retryUntil(() -> true)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilFalseJust() {
+        Maybe.just(1)
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilTrueEmpty() {
+        Maybe.empty()
+        .retryUntil(() -> true)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilFalseEmpty() {
+        Maybe.empty()
+        .retryUntil(() -> false)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilTrueError() {
+        Maybe.error(new TestException())
+        .retryUntil(() -> true)
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void untilFalseError() {
+        AtomicInteger counter = new AtomicInteger();
+        Maybe.defer(() -> {
+            if (counter.getAndIncrement() == 0) {
+                return Maybe.error(new TestException());
+            }
+            return Maybe.just(1);
+        })
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/single/SingleRetryTest.java b/src/test/java/io/reactivex/rxjava3/single/SingleRetryTest.java
index 1d5a1bff33..2fe5fa9f49 100644
--- a/src/test/java/io/reactivex/rxjava3/single/SingleRetryTest.java
+++ b/src/test/java/io/reactivex/rxjava3/single/SingleRetryTest.java
@@ -21,6 +21,7 @@
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.Predicate;
 import io.reactivex.rxjava3.internal.functions.Functions;
 
@@ -120,4 +121,42 @@ public void retryTimesPredicateWithZeroRetries() {
 
         assertEquals(1, numberOfSubscribeCalls.get());
     }
+
+    @Test
+    public void untilTrueJust() {
+        Single.just(1)
+        .retryUntil(() -> true)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilFalseJust() {
+        Single.just(1)
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilTrueError() {
+        Single.error(new TestException())
+        .retryUntil(() -> true)
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void untilFalseError() {
+        AtomicInteger counter = new AtomicInteger();
+        Single.defer(() -> {
+            if (counter.getAndIncrement() == 0) {
+                return Single.error(new TestException());
+            }
+            return Single.just(1);
+        })
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
 }

From 2fafcb03dd3e420b184608b13a40a5a3482f3cd7 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 13:36:49 +0100
Subject: [PATCH 15/37] 3.x: Add Maybe/Single/Completable switchOnNext &
 switchOnNextDelayError (#6870)

* 3.x: Add M/S/C switchOnNext[DelayError]

* Fix wording of the Completable variant
---
 .../reactivex/rxjava3/core/Completable.java   |  66 +++++++++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  71 ++++++++++
 .../io/reactivex/rxjava3/core/Single.java     |  72 +++++++++-
 ...FlowableSwitchMapCompletablePublisher.java |  46 ++++++
 .../FlowableSwitchMapMaybePublisher.java      |  48 +++++++
 .../FlowableSwitchMapSinglePublisher.java     |  48 +++++++
 .../CompletableSwitchOnNextTest.java          | 132 ++++++++++++++++++
 .../maybe/MaybeSwitchOnNextTest.java          | 123 ++++++++++++++++
 .../single/SingleSwitchOnNextTest.java        | 123 ++++++++++++++++
 9 files changed, 728 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapCompletablePublisher.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapMaybePublisher.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapSinglePublisher.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSwitchOnNextTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSwitchOnNextTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSwitchOnNextTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 81028f726e..779d04d1d2 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -1016,6 +1016,71 @@ private static NullPointerException toNpe(Throwable ex) {
         return npe;
     }
 
+    /**
+     * Switches between {@link CompletableSource}s emitted by the source {@link Publisher} whenever
+     * a new {@code CompletableSource} is emitted, disposing the previously running {@code CompletableSource},
+     * exposing the setup as a {@code Completable} sequence.
+     * <p>
+     * <img width="640" height="518" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.switchOnNext.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code switchOnNext} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>The returned sequence fails with the first error signaled by the {@code sources} {@code Publisher}
+     *  or the currently running {@code CompletableSource}, disposing the rest. Late errors are
+     *  forwarded to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.</dd>
+     * </dl>
+     * @param sources the {@code Publisher} sequence of inner {@code CompletableSource}s to switch between
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     * @see #switchOnNextDelayError(Publisher)
+     * @see <a href="http://reactivex.io/documentation/operators/switch.html">ReactiveX operators documentation: Switch</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
+    public static Completable switchOnNext(@NonNull Publisher<@NonNull ? extends CompletableSource> sources) {
+        Objects.requireNonNull(sources, "sources is null");
+        return RxJavaPlugins.onAssembly(new FlowableSwitchMapCompletablePublisher<>(sources, Functions.identity(), false));
+    }
+
+    /**
+     * Switches between {@link CompletableSource}s emitted by the source {@link Publisher} whenever
+     * a new {@code CompletableSource} is emitted, disposing the previously running {@code CompletableSource},
+     * exposing the setup as a {@code Completable} sequence and delaying all errors from
+     * all of them until all terminate.
+     * <p>
+     * <img width="640" height="415" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.switchOnNextDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code switchOnNextDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>The returned {@code Completable} collects all errors emitted by either the {@code sources}
+     *  {@code Publisher} or any inner {@code CompletableSource} and emits them as a {@link CompositeException}
+     *  when all sources terminate. If only one source ever failed, its error is emitted as-is at the end.</dd>
+     * </dl>
+     * @param sources the {@code Publisher} sequence of inner {@code CompletableSource}s to switch between
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     * @see #switchOnNext(Publisher)
+     * @see <a href="http://reactivex.io/documentation/operators/switch.html">ReactiveX operators documentation: Switch</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
+    public static Completable switchOnNextDelayError(@NonNull Publisher<@NonNull ? extends CompletableSource> sources) {
+        Objects.requireNonNull(sources, "sources is null");
+        return RxJavaPlugins.onAssembly(new FlowableSwitchMapCompletablePublisher<>(sources, Functions.identity(), true));
+    }
+
     /**
      * Returns a {@code Completable} instance which manages a resource along
      * with a custom {@link CompletableSource} instance while the subscription is active.
@@ -2328,6 +2393,7 @@ public final Completable retry(@NonNull Predicate<? super Throwable> predicate)
      * @param stop the function that should return {@code true} to stop retrying
      * @return the new {@code Completable} instance
      * @throws NullPointerException if {@code stop} is {@code null}
+     * @since 3.0.0
      */
     @CheckReturnValue
     @NonNull
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 98065a40d5..048b5ec713 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -1728,6 +1728,75 @@ public static <T> Single<Boolean> sequenceEqual(@NonNull MaybeSource<? extends T
         return RxJavaPlugins.onAssembly(new MaybeEqualSingle<>(source1, source2, isEqual));
     }
 
+    /**
+     * Switches between {@link MaybeSource}s emitted by the source {@link Publisher} whenever
+     * a new {@code MaybeSource} is emitted, disposing the previously running {@code MaybeSource},
+     * exposing the success items as a {@link Flowable} sequence.
+     * <p>
+     * <img width="640" height="521" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchOnNext.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).
+     *  The returned {@code Flowable} respects the backpressure from the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code switchOnNext} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>The returned sequence fails with the first error signaled by the {@code sources} {@code Publisher}
+     *  or the currently running {@code MaybeSource}, disposing the rest. Late errors are
+     *  forwarded to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.</dd>
+     * </dl>
+     * @param <T> the element type of the {@code MaybeSource}s
+     * @param sources the {@code Publisher} sequence of inner {@code MaybeSource}s to switch between
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     * @see #switchOnNextDelayError(Publisher)
+     * @see <a href="http://reactivex.io/documentation/operators/switch.html">ReactiveX operators documentation: Switch</a>
+     */
+    @BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> switchOnNext(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources) {
+        Objects.requireNonNull(sources, "sources is null");
+        return RxJavaPlugins.onAssembly(new FlowableSwitchMapMaybePublisher<>(sources, Functions.identity(), false));
+    }
+
+    /**
+     * Switches between {@link MaybeSource}s emitted by the source {@link Publisher} whenever
+     * a new {@code MaybeSource} is emitted, disposing the previously running {@code MaybeSource},
+     * exposing the success items as a {@link Flowable} sequence and delaying all errors from
+     * all of them until all terminate.
+     * <p>
+     * <img width="640" height="423" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchOnNextDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).
+     *  The returned {@code Flowable} respects the backpressure from the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code switchOnNextDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>The returned {@code Flowable} collects all errors emitted by either the {@code sources}
+     *  {@code Publisher} or any inner {@code MaybeSource} and emits them as a {@link CompositeException}
+     *  when all sources terminate. If only one source ever failed, its error is emitted as-is at the end.</dd>
+     * </dl>
+     * @param <T> the element type of the {@code MaybeSource}s
+     * @param sources the {@code Publisher} sequence of inner {@code MaybeSource}s to switch between
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     * @see #switchOnNext(Publisher)
+     * @see <a href="http://reactivex.io/documentation/operators/switch.html">ReactiveX operators documentation: Switch</a>
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> switchOnNextDelayError(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources) {
+        Objects.requireNonNull(sources, "sources is null");
+        return RxJavaPlugins.onAssembly(new FlowableSwitchMapMaybePublisher<>(sources, Functions.identity(), true));
+    }
+
     /**
      * Returns a {@code Maybe} that emits {@code 0L} after a specified delay.
      * <p>
@@ -2868,6 +2937,7 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit) {
      * @throws NullPointerException if {@code unit} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
      * @see #delay(long, TimeUnit, Scheduler, boolean)
+     * @since 3.0.0
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.COMPUTATION)
@@ -2922,6 +2992,7 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Schedule
      * @return the new {@code Maybe} instance
      * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
+     * @since 3.0.0
      */
     @CheckReturnValue
     @NonNull
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index e17ff9e8ec..719719520f 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -30,7 +30,7 @@
 import io.reactivex.rxjava3.internal.operators.completable.*;
 import io.reactivex.rxjava3.internal.operators.flowable.*;
 import io.reactivex.rxjava3.internal.operators.maybe.*;
-import io.reactivex.rxjava3.internal.operators.mixed.SingleFlatMapObservable;
+import io.reactivex.rxjava3.internal.operators.mixed.*;
 import io.reactivex.rxjava3.internal.operators.observable.*;
 import io.reactivex.rxjava3.internal.operators.single.*;
 import io.reactivex.rxjava3.internal.util.ErrorMode;
@@ -1406,6 +1406,75 @@ public static <T> Single<Boolean> sequenceEqual(@NonNull SingleSource<? extends
         return RxJavaPlugins.onAssembly(new SingleEquals<>(source1, source2));
     }
 
+    /**
+     * Switches between {@link SingleSource}s emitted by the source {@link Publisher} whenever
+     * a new {@code SingleSource} is emitted, disposing the previously running {@code SingleSource},
+     * exposing the success items as a {@link Flowable} sequence.
+     * <p>
+     * <img width="640" height="521" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.switchOnNext.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).
+     *  The returned {@code Flowable} respects the backpressure from the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code switchOnNext} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>The returned sequence fails with the first error signaled by the {@code sources} {@code Publisher}
+     *  or the currently running {@code SingleSource}, disposing the rest. Late errors are
+     *  forwarded to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.</dd>
+     * </dl>
+     * @param <T> the element type of the {@code SingleSource}s
+     * @param sources the {@code Publisher} sequence of inner {@code SingleSource}s to switch between
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     * @see #switchOnNextDelayError(Publisher)
+     * @see <a href="http://reactivex.io/documentation/operators/switch.html">ReactiveX operators documentation: Switch</a>
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> switchOnNext(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
+        Objects.requireNonNull(sources, "sources is null");
+        return RxJavaPlugins.onAssembly(new FlowableSwitchMapSinglePublisher<>(sources, Functions.identity(), false));
+    }
+
+    /**
+     * Switches between {@link SingleSource}s emitted by the source {@link Publisher} whenever
+     * a new {@code SingleSource} is emitted, disposing the previously running {@code SingleSource},
+     * exposing the success items as a {@link Flowable} sequence and delaying all errors from
+     * all of them until all terminate.
+     * <p>
+     * <img width="640" height="425" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchOnNextDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).
+     *  The returned {@code Flowable} respects the backpressure from the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code switchOnNextDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>The returned {@code Flowable} collects all errors emitted by either the {@code sources}
+     *  {@code Publisher} or any inner {@code SingleSource} and emits them as a {@link CompositeException}
+     *  when all sources terminate. If only one source ever failed, its error is emitted as-is at the end.</dd>
+     * </dl>
+     * @param <T> the element type of the {@code SingleSource}s
+     * @param sources the {@code Publisher} sequence of inner {@code SingleSource}s to switch between
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     * @see #switchOnNext(Publisher)
+     * @see <a href="http://reactivex.io/documentation/operators/switch.html">ReactiveX operators documentation: Switch</a>
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> switchOnNextDelayError(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
+        Objects.requireNonNull(sources, "sources is null");
+        return RxJavaPlugins.onAssembly(new FlowableSwitchMapSinglePublisher<>(sources, Functions.identity(), true));
+    }
+
     /**
      * <strong>Advanced use only:</strong> creates a {@code Single} instance without
      * any safeguards by using a callback that is called with a {@link SingleObserver}.
@@ -3758,6 +3827,7 @@ public final Single<T> retry(@NonNull Predicate<? super Throwable> predicate) {
      * @param stop the function that should return {@code true} to stop retrying
      * @return the new {@code Single} instance
      * @throws NullPointerException if {@code stop} is {@code null}
+     * @since 3.0.0
      */
     @CheckReturnValue
     @NonNull
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapCompletablePublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapCompletablePublisher.java
new file mode 100644
index 0000000000..5752027c23
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapCompletablePublisher.java
@@ -0,0 +1,46 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.mixed;
+
+import org.reactivestreams.Publisher;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.Function;
+
+/**
+ * Switch between subsequent {@link CompletableSource}s emitted by a {@link Publisher}.
+ * Reuses {@link FlowableSwitchMapCompletable} internals.
+ * @param <T> the upstream value type
+ * @since 3.0.0
+ */
+public final class FlowableSwitchMapCompletablePublisher<T> extends Completable {
+
+    final Publisher<T> source;
+
+    final Function<? super T, ? extends CompletableSource> mapper;
+
+    final boolean delayErrors;
+
+    public FlowableSwitchMapCompletablePublisher(Publisher<T> source,
+            Function<? super T, ? extends CompletableSource> mapper, boolean delayErrors) {
+        this.source = source;
+        this.mapper = mapper;
+        this.delayErrors = delayErrors;
+    }
+
+    @Override
+    protected void subscribeActual(CompletableObserver observer) {
+        source.subscribe(new FlowableSwitchMapCompletable.SwitchMapCompletableObserver<>(observer, mapper, delayErrors));
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapMaybePublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapMaybePublisher.java
new file mode 100644
index 0000000000..41696133e9
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapMaybePublisher.java
@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.mixed;
+
+import org.reactivestreams.*;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.Function;
+
+/**
+ * Switch between subsequent {@link MaybeSource}s emitted by a {@link Publisher}.
+ * Reuses {@link FlowableSwitchMapMaybe} internals.
+ * @param <T> the upstream value type
+ * @param <R> the downstream value type
+ * @since 3.0.0
+ */
+public final class FlowableSwitchMapMaybePublisher<T, R> extends Flowable<R> {
+
+    final Publisher<T> source;
+
+    final Function<? super T, ? extends MaybeSource<? extends R>> mapper;
+
+    final boolean delayErrors;
+
+    public FlowableSwitchMapMaybePublisher(Publisher<T> source,
+            Function<? super T, ? extends MaybeSource<? extends R>> mapper,
+            boolean delayErrors) {
+        this.source = source;
+        this.mapper = mapper;
+        this.delayErrors = delayErrors;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super R> s) {
+        source.subscribe(new FlowableSwitchMapMaybe.SwitchMapMaybeSubscriber<>(s, mapper, delayErrors));
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapSinglePublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapSinglePublisher.java
new file mode 100644
index 0000000000..e64f839046
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableSwitchMapSinglePublisher.java
@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.mixed;
+
+import org.reactivestreams.*;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.Function;
+
+/**
+ * Switch between subsequent {@link SingleSource}s emitted by a {@link Publisher}.
+ * Reuses {@link FlowableSwitchMapSingle} internals.
+ * @param <T> the upstream value type
+ * @param <R> the downstream value type
+ * @since 3.0.0
+ */
+public final class FlowableSwitchMapSinglePublisher<T, R> extends Flowable<R> {
+
+    final Publisher<T> source;
+
+    final Function<? super T, ? extends SingleSource<? extends R>> mapper;
+
+    final boolean delayErrors;
+
+    public FlowableSwitchMapSinglePublisher(Publisher<T> source,
+            Function<? super T, ? extends SingleSource<? extends R>> mapper,
+            boolean delayErrors) {
+        this.source = source;
+        this.mapper = mapper;
+        this.delayErrors = delayErrors;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super R> s) {
+        source.subscribe(new FlowableSwitchMapSingle.SwitchMapSingleSubscriber<>(s, mapper, delayErrors));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSwitchOnNextTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSwitchOnNextTest.java
new file mode 100644
index 0000000000..ad6147fef5
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSwitchOnNextTest.java
@@ -0,0 +1,132 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.processors.PublishProcessor;
+import io.reactivex.rxjava3.subjects.CompletableSubject;
+
+public class CompletableSwitchOnNextTest extends RxJavaTest {
+
+    @Test
+    public void normal() {
+        Runnable run = mock(Runnable.class);
+
+        Completable.switchOnNext(
+                Flowable.range(1, 10)
+                .map(v -> {
+                    if (v % 2 == 0) {
+                        return Completable.fromRunnable(run);
+                    }
+                    return Completable.complete();
+                })
+        )
+        .test()
+        .assertResult();
+
+        verify(run, times(5)).run();
+    }
+
+    @Test
+    public void normalDelayError() {
+        Runnable run = mock(Runnable.class);
+
+        Completable.switchOnNextDelayError(
+                Flowable.range(1, 10)
+                .map(v -> {
+                    if (v % 2 == 0) {
+                        return Completable.fromRunnable(run);
+                    }
+                    return Completable.complete();
+                })
+        )
+        .test()
+        .assertResult();
+
+        verify(run, times(5)).run();
+    }
+
+    @Test
+    public void noDelaySwitch() {
+        PublishProcessor<Completable> pp = PublishProcessor.create();
+
+        TestObserver<Void> to = Completable.switchOnNext(pp).test();
+
+        assertTrue(pp.hasSubscribers());
+
+        to.assertEmpty();
+
+        CompletableSubject cs1 = CompletableSubject.create();
+        CompletableSubject cs2 = CompletableSubject.create();
+
+        pp.onNext(cs1);
+
+        assertTrue(cs1.hasObservers());
+
+        pp.onNext(cs2);
+
+        assertFalse(cs1.hasObservers());
+        assertTrue(cs2.hasObservers());
+
+        pp.onComplete();
+
+        assertTrue(cs2.hasObservers());
+
+        cs2.onComplete();
+
+        to.assertResult();
+    }
+
+    @Test
+    public void delaySwitch() {
+        PublishProcessor<Completable> pp = PublishProcessor.create();
+
+        TestObserver<Void> to = Completable.switchOnNextDelayError(pp).test();
+
+        assertTrue(pp.hasSubscribers());
+
+        to.assertEmpty();
+
+        CompletableSubject cs1 = CompletableSubject.create();
+        CompletableSubject cs2 = CompletableSubject.create();
+
+        pp.onNext(cs1);
+
+        assertTrue(cs1.hasObservers());
+
+        pp.onNext(cs2);
+
+        assertFalse(cs1.hasObservers());
+        assertTrue(cs2.hasObservers());
+
+        assertTrue(cs2.hasObservers());
+
+        cs2.onError(new TestException());
+
+        assertTrue(pp.hasSubscribers());
+
+        to.assertEmpty();
+
+        pp.onComplete();
+
+        to.assertFailure(TestException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSwitchOnNextTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSwitchOnNextTest.java
new file mode 100644
index 0000000000..6b217aa680
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSwitchOnNextTest.java
@@ -0,0 +1,123 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.processors.PublishProcessor;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+
+public class MaybeSwitchOnNextTest extends RxJavaTest {
+
+    @Test
+    public void normal() {
+        Maybe.switchOnNext(
+                Flowable.range(1, 10)
+                .map(v -> {
+                    if (v % 2 == 0) {
+                        return Maybe.just(v);
+                    }
+                    return Maybe.empty();
+                })
+        )
+        .test()
+        .assertResult(2, 4, 6, 8, 10);
+    }
+
+    @Test
+    public void normalDelayError() {
+        Maybe.switchOnNextDelayError(
+                Flowable.range(1, 10)
+                .map(v -> {
+                    if (v % 2 == 0) {
+                        return Maybe.just(v);
+                    }
+                    return Maybe.empty();
+                })
+        )
+        .test()
+        .assertResult(2, 4, 6, 8, 10);
+    }
+
+    @Test
+    public void noDelaySwitch() {
+        PublishProcessor<Maybe<Integer>> pp = PublishProcessor.create();
+
+        TestSubscriber<Integer> ts = Maybe.switchOnNext(pp).test();
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.assertEmpty();
+
+        MaybeSubject<Integer> ms1 = MaybeSubject.create();
+        MaybeSubject<Integer> ms2 = MaybeSubject.create();
+
+        pp.onNext(ms1);
+
+        assertTrue(ms1.hasObservers());
+
+        pp.onNext(ms2);
+
+        assertFalse(ms1.hasObservers());
+        assertTrue(ms2.hasObservers());
+
+        pp.onComplete();
+
+        assertTrue(ms2.hasObservers());
+
+        ms2.onSuccess(1);
+
+        ts.assertResult(1);
+    }
+
+    @Test
+    public void delaySwitch() {
+        PublishProcessor<Maybe<Integer>> pp = PublishProcessor.create();
+
+        TestSubscriber<Integer> ts = Maybe.switchOnNextDelayError(pp).test();
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.assertEmpty();
+
+        MaybeSubject<Integer> ms1 = MaybeSubject.create();
+        MaybeSubject<Integer> ms2 = MaybeSubject.create();
+
+        pp.onNext(ms1);
+
+        assertTrue(ms1.hasObservers());
+
+        pp.onNext(ms2);
+
+        assertFalse(ms1.hasObservers());
+        assertTrue(ms2.hasObservers());
+
+        assertTrue(ms2.hasObservers());
+
+        ms2.onError(new TestException());
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.assertEmpty();
+
+        pp.onComplete();
+
+        ts.assertFailure(TestException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSwitchOnNextTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSwitchOnNextTest.java
new file mode 100644
index 0000000000..63c97f14ec
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSwitchOnNextTest.java
@@ -0,0 +1,123 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.processors.PublishProcessor;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+
+public class SingleSwitchOnNextTest extends RxJavaTest {
+
+    @Test
+    public void normal() {
+        Single.switchOnNext(
+                Flowable.range(1, 5)
+                .map(v -> {
+                    if (v % 2 == 0) {
+                        return Single.just(v);
+                    }
+                    return Single.just(10 + v);
+                })
+        )
+        .test()
+        .assertResult(11, 2, 13, 4, 15);
+    }
+
+    @Test
+    public void normalDelayError() {
+        Single.switchOnNextDelayError(
+                Flowable.range(1, 5)
+                .map(v -> {
+                    if (v % 2 == 0) {
+                        return Single.just(v);
+                    }
+                    return Single.just(10 + v);
+                })
+        )
+        .test()
+        .assertResult(11, 2, 13, 4, 15);
+    }
+
+    @Test
+    public void noDelaySwitch() {
+        PublishProcessor<Single<Integer>> pp = PublishProcessor.create();
+
+        TestSubscriber<Integer> ts = Single.switchOnNext(pp).test();
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.assertEmpty();
+
+        SingleSubject<Integer> ss1 = SingleSubject.create();
+        SingleSubject<Integer> ss2 = SingleSubject.create();
+
+        pp.onNext(ss1);
+
+        assertTrue(ss1.hasObservers());
+
+        pp.onNext(ss2);
+
+        assertFalse(ss1.hasObservers());
+        assertTrue(ss2.hasObservers());
+
+        pp.onComplete();
+
+        assertTrue(ss2.hasObservers());
+
+        ss2.onSuccess(1);
+
+        ts.assertResult(1);
+    }
+
+    @Test
+    public void delaySwitch() {
+        PublishProcessor<Single<Integer>> pp = PublishProcessor.create();
+
+        TestSubscriber<Integer> ts = Single.switchOnNextDelayError(pp).test();
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.assertEmpty();
+
+        SingleSubject<Integer> ss1 = SingleSubject.create();
+        SingleSubject<Integer> ss2 = SingleSubject.create();
+
+        pp.onNext(ss1);
+
+        assertTrue(ss1.hasObservers());
+
+        pp.onNext(ss2);
+
+        assertFalse(ss1.hasObservers());
+        assertTrue(ss2.hasObservers());
+
+        assertTrue(ss2.hasObservers());
+
+        ss2.onError(new TestException());
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.assertEmpty();
+
+        pp.onComplete();
+
+        ts.assertFailure(TestException.class);
+    }
+}

From 611bb3f04dd99bfb141500f304d7a0c44fbfd5db Mon Sep 17 00:00:00 2001
From: akarnokd <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 13:41:04 +0100
Subject: [PATCH 16/37] Fix minor JavaDocs syntax errors

---
 src/main/java/io/reactivex/rxjava3/core/Flowable.java | 2 +-
 src/main/java/io/reactivex/rxjava3/core/Maybe.java    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index a627eb3474..d1b17e8b84 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -11960,7 +11960,7 @@ public final <U> Flowable<U> ofType(@NonNull Class<U> clazz) {
      *
      * @return the new {@code Flowable} instance
      * @see <a href="http://reactivex.io/documentation/operators/backpressure.html">ReactiveX operators documentation: backpressure operators</a>
-     * #see {@link #onBackpressureBuffer(boolean)}
+     * @see #onBackpressureBuffer(boolean)
      */
     @CheckReturnValue
     @BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 048b5ec713..8699d60e16 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -2659,7 +2659,7 @@ public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess, @Non
      * </dl>
      * @param onSuccess the {@link Consumer} to call if the current {@code Maybe} succeeds
      * @param onError the {@code Consumer} to call if the current {@code Maybe} signals an error
-     * @param onComplete the {@linnk Action} to call if the current {@code Maybe} completes without a value
+     * @param onComplete the {@link Action} to call if the current {@code Maybe} completes without a value
      * @throws NullPointerException if {@code onSuccess}, {@code onError} or {@code onComplete} is {@code null}
      * @since 3.0.0
      */

From 53ba4352c447562ccbba507f4d4f5493a07ab889 Mon Sep 17 00:00:00 2001
From: akarnokd <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 13:44:29 +0100
Subject: [PATCH 17/37] Refresh operator-matrix

---
 docs/Operator-Matrix.md | 40 ++++++++++++++++------------------------
 1 file changed, 16 insertions(+), 24 deletions(-)

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 1259584fea..3eaaa51221 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -166,7 +166,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='repeatWhen'></a>`repeatWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='replay'></a>`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
 <a name='retry'></a>`retry`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='retryWhen'></a>`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
@@ -201,8 +201,8 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
-<a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
 <a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
 <a name='takeUntil'></a>`takeUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -396,24 +396,16 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 42. Single.ofType()
 43. Completable.onErrorReturn()
 44. Completable.onErrorReturnItem()
-45. Single.retryUntil()
-46. Completable.retryUntil()
-47. Maybe.safeSubscribe()
-48. Single.safeSubscribe()
-49. Completable.safeSubscribe()
-50. Completable.sequenceEqual()
-51. Maybe.startWith()
-52. Single.startWith()
-53. Maybe.switchOnNext()
-54. Single.switchOnNext()
-55. Completable.switchOnNext()
-56. Maybe.switchOnNextDelayError()
-57. Single.switchOnNextDelayError()
-58. Completable.switchOnNextDelayError()
-59. Maybe.timeInterval()
-60. Single.timeInterval()
-61. Completable.timeInterval()
-62. Maybe.timestamp()
-63. Single.timestamp()
-64. Maybe.toFuture()
-65. Completable.toFuture()
+45. Maybe.safeSubscribe()
+46. Single.safeSubscribe()
+47. Completable.safeSubscribe()
+48. Completable.sequenceEqual()
+49. Maybe.startWith()
+50. Single.startWith()
+51. Maybe.timeInterval()
+52. Single.timeInterval()
+53. Completable.timeInterval()
+54. Maybe.timestamp()
+55. Single.timestamp()
+56. Maybe.toFuture()
+57. Completable.toFuture()

From ea8ab3bbd5617af2e0f5342c72a42a0eeae941ee Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 16:58:59 +0100
Subject: [PATCH 18/37] 3.x: Add Maybe.dematerialize (#6871)

---
 .../java/io/reactivex/rxjava3/core/Maybe.java |  41 ++++++
 .../io/reactivex/rxjava3/core/Single.java     |   2 +-
 .../operators/maybe/MaybeDematerialize.java   | 108 ++++++++++++++++
 .../maybe/MaybeDematerializeTest.java         | 122 ++++++++++++++++++
 4 files changed, 272 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerialize.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerializeTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 8699d60e16..a9435534f6 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -2893,6 +2893,47 @@ public final Single<T> defaultIfEmpty(@NonNull T defaultItem) {
         return RxJavaPlugins.onAssembly(new MaybeToSingle<>(this, defaultItem));
     }
 
+    /**
+     * Maps the {@link Notification} success value of the current {@code Maybe} back into normal
+     * {@code onSuccess}, {@code onError} or {@code onComplete} signals.
+     * <p>
+     * <img width="640" height="268" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.dematerialize.png" alt="">
+     * <p>
+     * The intended use of the {@code selector} function is to perform a
+     * type-safe identity mapping (see example) on a source that is already of type
+     * {@code Notification<T>}. The Java language doesn't allow
+     * limiting instance methods to a certain generic argument shape, therefore,
+     * a function is used to ensure the conversion remains type safe.
+     * <p>
+     * Regular {@code onError} or {@code onComplete} signals from the current {@code Maybe} are passed along to the downstream.
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code dematerialize} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * <p>
+     * Example:
+     * <pre><code>
+     * Maybe.just(Notification.createOnNext(1))
+     * .dematerialize(notification -&gt; notification)
+     * .test()
+     * .assertResult(1);
+     * </code></pre>
+     * @param <R> the result type
+     * @param selector the function called with the success item and should
+     * return a {@code Notification} instance.
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code selector} is {@code null}
+     * @since 3.0.0
+     * @see #materialize()
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <@NonNull R> Maybe<R> dematerialize(@NonNull Function<? super T, @NonNull Notification<R>> selector) {
+        Objects.requireNonNull(selector, "selector is null");
+        return RxJavaPlugins.onAssembly(new MaybeDematerialize<>(this, selector));
+    }
+
     /**
      * Returns a {@code Maybe} that signals the events emitted by the current {@code Maybe} shifted forward in time by a
      * specified delay.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 719719520f..3bfcd78a9c 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -2511,7 +2511,7 @@ public final Single<T> delaySubscription(long time, @NonNull TimeUnit unit, @Non
     }
 
     /**
-     * Maps the {@link Notification} success value of this {@code Single} back into normal
+     * Maps the {@link Notification} success value of the current {@code Single} back into normal
      * {@code onSuccess}, {@code onError} or {@code onComplete} signals as a
      * {@link Maybe} source.
      * <p>
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerialize.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerialize.java
new file mode 100644
index 0000000000..d5d3ed25cd
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerialize.java
@@ -0,0 +1,108 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+
+import java.util.Objects;
+
+/**
+ * Maps the success value of the source to a Notification, then
+ * maps it back to the corresponding signal type.
+ * <p>History: 2.2.4 - experimental
+ * @param <T> the element type of the source
+ * @param <R> the element type of the Notification and result
+ * @since 3.0.0
+ */
+public final class MaybeDematerialize<T, R> extends AbstractMaybeWithUpstream<T, R> {
+
+    final Function<? super T, Notification<R>> selector;
+
+    public MaybeDematerialize(Maybe<T> source, Function<? super T, Notification<R>> selector) {
+        super(source);
+        this.selector = selector;
+    }
+
+    @Override
+    protected void subscribeActual(MaybeObserver<? super R> observer) {
+        source.subscribe(new DematerializeObserver<>(observer, selector));
+    }
+
+    static final class DematerializeObserver<T, R> implements MaybeObserver<T>, Disposable {
+
+        final MaybeObserver<? super R> downstream;
+
+        final Function<? super T, Notification<R>> selector;
+
+        Disposable upstream;
+
+        DematerializeObserver(MaybeObserver<? super R> downstream,
+                Function<? super T, Notification<R>> selector) {
+            this.downstream = downstream;
+            this.selector = selector;
+        }
+
+        @Override
+        public void dispose() {
+            upstream.dispose();
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.validate(upstream, d)) {
+                upstream = d;
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(T t) {
+            Notification<R> notification;
+
+            try {
+                notification = Objects.requireNonNull(selector.apply(t), "The selector returned a null Notification");
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                downstream.onError(ex);
+                return;
+            }
+            if (notification.isOnNext()) {
+                downstream.onSuccess(notification.getValue());
+            } else if (notification.isOnComplete()) {
+                downstream.onComplete();
+            } else {
+                downstream.onError(notification.getError());
+            }
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            downstream.onError(e);
+        }
+
+        @Override
+        public void onComplete() {
+            downstream.onComplete();
+        }
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerializeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerializeTest.java
new file mode 100644
index 0000000000..5c75a92a10
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDematerializeTest.java
@@ -0,0 +1,122 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.mockito.Mockito.*;
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.functions.Functions;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeDematerializeTest extends RxJavaTest {
+
+    @Test
+    public void success() {
+        Maybe.just(Notification.createOnNext(1))
+        .dematerialize(Functions.<Notification<Integer>>identity())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void empty() {
+        Maybe.just(Notification.<Integer>createOnComplete())
+        .dematerialize(Functions.<Notification<Integer>>identity())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void emptySource() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Function<Notification<Integer>, Notification<Integer>> function = mock(Function.class);
+
+        Maybe.<Notification<Integer>>empty()
+        .dematerialize(function)
+        .test()
+        .assertResult();
+
+        verify(function, never()).apply(any());
+    }
+
+    @Test
+    public void error() {
+        Maybe.<Notification<Integer>>error(new TestException())
+        .dematerialize(Functions.<Notification<Integer>>identity())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void errorNotification() {
+        Maybe.just(Notification.<Integer>createOnError(new TestException()))
+        .dematerialize(Functions.<Notification<Integer>>identity())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeMaybe(new Function<Maybe<Object>, MaybeSource<Object>>() {
+            @SuppressWarnings({ "unchecked", "rawtypes" })
+            @Override
+            public MaybeSource<Object> apply(Maybe<Object> v) throws Exception {
+                return v.dematerialize((Function)Functions.identity());
+            }
+        });
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(MaybeSubject.<Notification<Integer>>create().dematerialize(Functions.<Notification<Integer>>identity()));
+    }
+
+    @Test
+    public void selectorCrash() {
+        Maybe.just(Notification.createOnNext(1))
+        .dematerialize(new Function<Notification<Integer>, Notification<Integer>>() {
+            @Override
+            public Notification<Integer> apply(Notification<Integer> v) throws Exception {
+                throw new TestException();
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void selectorNull() {
+        Maybe.just(Notification.createOnNext(1))
+        .dematerialize(Functions.justFunction((Notification<Integer>)null))
+        .test()
+        .assertFailure(NullPointerException.class);
+    }
+
+    @Test
+    public void selectorDifferentType() {
+        Maybe.just(Notification.createOnNext(1))
+        .dematerialize(new Function<Notification<Integer>, Notification<String>>() {
+            @Override
+            public Notification<String> apply(Notification<Integer> v) throws Exception {
+                return Notification.createOnNext("Value-" + 1);
+            }
+        })
+        .test()
+        .assertResult("Value-1");
+    }
+}

From 26dacd72f1929c78d84da41ec80dc1ae3996c9f9 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sat, 25 Jan 2020 22:07:48 +0100
Subject: [PATCH 19/37] 3.x: Add many fromX operators + marbles (#6873)

---
 docs/Operator-Matrix.md                       |  67 +++---
 .../reactivex/rxjava3/core/Completable.java   |   6 +-
 .../io/reactivex/rxjava3/core/Flowable.java   | 209 ++++++++++++++++-
 .../java/io/reactivex/rxjava3/core/Maybe.java |  61 ++++-
 .../io/reactivex/rxjava3/core/Observable.java | 130 +++++++++++
 .../io/reactivex/rxjava3/core/Single.java     |  50 ++++
 .../fuseable/AbstractEmptyQueueFuseable.java  |  76 ++++++
 .../fuseable/CancellableQueueFuseable.java    |  42 ++++
 .../SubscriberCompletableObserver.java        |  59 -----
 .../completable/CompletableFromAction.java    |  24 +-
 .../completable/CompletableFromRunnable.java  |  24 +-
 .../completable/CompletableToFlowable.java    |   5 +-
 .../completable/CompletableToObservable.java  |  66 +-----
 .../FlowableElementAtMaybePublisher.java      |  42 ++++
 .../flowable/FlowableFromAction.java          |  68 ++++++
 .../flowable/FlowableFromCompletable.java     |  86 +++++++
 .../flowable/FlowableFromObservable.java      |   5 +-
 .../flowable/FlowableFromRunnable.java        |  68 ++++++
 .../operators/maybe/MaybeFromCompletable.java |   2 +-
 .../operators/maybe/MaybeToSingle.java        |   2 +-
 .../observable/ObservableFromAction.java      |  66 ++++++
 .../observable/ObservableFromCompletable.java |  89 +++++++
 .../observable/ObservableFromRunnable.java    |  66 ++++++
 .../CancellableQueueFuseableTest.java         |  75 ++++++
 .../CompletableAndThenCompletableabTest.java  |   2 +-
 .../CompletableFromActionTest.java            |  16 +-
 .../CompletableFromRunnableTest.java          |  16 +-
 .../CompletableToObservableTest.java          |  38 ---
 .../flowable/FlowableFromActionTest.java      | 214 +++++++++++++++++
 .../flowable/FlowableFromCompletableTest.java | 196 ++++++++++++++++
 .../flowable/FlowableFromMaybeTest.java       |  93 ++++++++
 .../flowable/FlowableFromObservableTest.java  |  10 +
 .../flowable/FlowableFromRunnableTest.java    | 220 ++++++++++++++++++
 .../flowable/FlowableFromSingleTest.java      |  86 +++++++
 .../maybe/MaybeFromObservableTest.java        |  50 ++++
 .../maybe/MaybeFromPubisherTest.java          |  50 ++++
 .../observable/ObservableFromActionTest.java  | 214 +++++++++++++++++
 .../ObservableFromCompletableTest.java        | 195 ++++++++++++++++
 .../observable/ObservableFromMaybeTest.java   |  93 ++++++++
 .../ObservableFromRunnableTest.java           | 220 ++++++++++++++++++
 .../observable/ObservableFromSingleTest.java  |  86 +++++++
 .../operators/single/SingleFromMaybeTest.java |  72 ++++++
 .../util/OperatorMatrixGenerator.java         |  15 ++
 .../validators/InternalWrongNaming.java       |   5 +-
 44 files changed, 3032 insertions(+), 247 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/fuseable/AbstractEmptyQueueFuseable.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseable.java
 delete mode 100644 src/main/java/io/reactivex/rxjava3/internal/observers/SubscriberCompletableObserver.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableElementAtMaybePublisher.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromAction.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletable.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnable.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromAction.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletable.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnable.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromActionTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromMaybeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromSingleTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromObservableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromPubisherTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromActionTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromMaybeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromSingleTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFromMaybeTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 3eaaa51221..81e1f7878d 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -102,19 +102,19 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|
 <a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|
-<a name='fromAction'></a>`fromAction`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromAction'></a>`fromAction`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromArray'></a>`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
 <a name='fromCallable'></a>`fromCallable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromCompletable'></a>`fromCompletable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|
+<a name='fromCompletable'></a>`fromCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|
 <a name='fromCompletionStage'></a>`fromCompletionStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromFuture'></a>`fromFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromIterable'></a>`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
-<a name='fromMaybe'></a>`fromMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromObservable'></a>`fromObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromMaybe'></a>`fromMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromObservable'></a>`fromObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromOptional'></a>`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
-<a name='fromPublisher'></a>`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromRunnable'></a>`fromRunnable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromSingle'></a>`fromSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromPublisher'></a>`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromRunnable'></a>`fromRunnable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromSingle'></a>`fromSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromStream'></a>`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
 <a name='fromSupplier'></a>`fromSupplier`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='generate'></a>`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|
@@ -237,6 +237,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([108](#notes-108))</sup>|
 <a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([109](#notes-109))</sup>|
 <a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([110](#notes-110))</sup>|
+<a name='total'></a>**237 operators** | **215** | **209** | **108** | **93** | **76** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -375,37 +376,21 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 21. Maybe.doOnLifecycle()
 22. Single.doOnLifecycle()
 23. Completable.doOnLifecycle()
-24. Flowable.fromAction()
-25. Observable.fromAction()
-26. Single.fromAction()
-27. Flowable.fromCompletable()
-28. Observable.fromCompletable()
-29. Flowable.fromMaybe()
-30. Observable.fromMaybe()
-31. Single.fromMaybe()
-32. Flowable.fromObservable()
-33. Maybe.fromObservable()
-34. Maybe.fromPublisher()
-35. Flowable.fromRunnable()
-36. Observable.fromRunnable()
-37. Single.fromRunnable()
-38. Flowable.fromSingle()
-39. Observable.fromSingle()
-40. Single.mergeArray()
-41. Single.mergeArrayDelayError()
-42. Single.ofType()
-43. Completable.onErrorReturn()
-44. Completable.onErrorReturnItem()
-45. Maybe.safeSubscribe()
-46. Single.safeSubscribe()
-47. Completable.safeSubscribe()
-48. Completable.sequenceEqual()
-49. Maybe.startWith()
-50. Single.startWith()
-51. Maybe.timeInterval()
-52. Single.timeInterval()
-53. Completable.timeInterval()
-54. Maybe.timestamp()
-55. Single.timestamp()
-56. Maybe.toFuture()
-57. Completable.toFuture()
+24. Single.mergeArray()
+25. Single.mergeArrayDelayError()
+26. Single.ofType()
+27. Completable.onErrorReturn()
+28. Completable.onErrorReturnItem()
+29. Maybe.safeSubscribe()
+30. Single.safeSubscribe()
+31. Completable.safeSubscribe()
+32. Completable.sequenceEqual()
+33. Maybe.startWith()
+34. Single.startWith()
+35. Maybe.timeInterval()
+36. Single.timeInterval()
+37. Completable.timeInterval()
+38. Maybe.timestamp()
+39. Single.timestamp()
+40. Maybe.toFuture()
+41. Completable.toFuture()
diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 779d04d1d2..e965855e00 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -496,7 +496,7 @@ public static Completable fromFuture(@NonNull Future<?> future) {
     }
 
     /**
-     * Returns a {@code Completable} instance that when subscribed to, subscribes to the {@link Maybe} instance and
+     * Returns a {@code Completable} instance that when subscribed to, subscribes to the {@link MaybeSource} instance and
      * emits an {@code onComplete} event if the maybe emits {@code onSuccess}/{@code onComplete} or forwards any
      * {@code onError} events.
      * <p>
@@ -506,8 +506,8 @@ public static Completable fromFuture(@NonNull Future<?> future) {
      *  <dd>{@code fromMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * <p>History: 2.1.17 - beta
-     * @param <T> the value type of the {@link MaybeSource} element
-     * @param maybe the {@code Maybe} instance to subscribe to, not {@code null}
+     * @param <T> the value type of the {@code MaybeSource} element
+     * @param maybe the {@code MaybeSource} instance to subscribe to, not {@code null}
      * @return the new {@code Completable} instance
      * @throws NullPointerException if {@code maybe} is {@code null}
      * @since 2.2
diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index d1b17e8b84..3d83d477c5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -19,7 +19,6 @@
 import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
-import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.exceptions.*;
 import io.reactivex.rxjava3.flowables.*;
@@ -28,8 +27,10 @@
 import io.reactivex.rxjava3.internal.fuseable.ScalarSupplier;
 import io.reactivex.rxjava3.internal.jdk8.*;
 import io.reactivex.rxjava3.internal.operators.flowable.*;
+import io.reactivex.rxjava3.internal.operators.maybe.MaybeToFlowable;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
-import io.reactivex.rxjava3.internal.operators.observable.*;
+import io.reactivex.rxjava3.internal.operators.observable.ObservableFromPublisher;
+import io.reactivex.rxjava3.internal.operators.single.SingleToFlowable;
 import io.reactivex.rxjava3.internal.schedulers.ImmediateThinScheduler;
 import io.reactivex.rxjava3.internal.subscribers.*;
 import io.reactivex.rxjava3.internal.util.*;
@@ -1959,6 +1960,39 @@ public static <T> Flowable<T> error(@NonNull Throwable throwable) {
         return error(Functions.justSupplier(throwable));
     }
 
+    /**
+     * Returns a {@code Flowable} instance that runs the given {@link Action} for each subscriber and
+     * emits either its exception or simply completes.
+     * <p>
+     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromAction.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>This source doesn't produce any elements and effectively ignores downstream backpressure.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromAction} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd> If the {@code Action} throws an exception, the respective {@link Throwable} is
+     *  delivered to the downstream via {@link Subscriber#onError(Throwable)},
+     *  except when the downstream has canceled the resulting {@code Flowable} source.
+     *  In this latter case, the {@code Throwable} is delivered to the global error handler via
+     *  {@link RxJavaPlugins#onError(Throwable)} as an {@link io.reactivex.rxjava3.exceptions.UndeliverableException UndeliverableException}.
+     *  </dd>
+     * </dl>
+     * @param <T> the target type
+     * @param action the {@code Action} to run for each subscriber
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code action} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
+    public static <T> Flowable<T> fromAction(@NonNull Action action) {
+        Objects.requireNonNull(action, "action is null");
+        return RxJavaPlugins.onAssembly(new FlowableFromAction<>(action));
+    }
+
     /**
      * Converts an array into a {@link Publisher} that emits the items in the array.
      * <p>
@@ -2037,6 +2071,30 @@ public static <T> Flowable<T> error(@NonNull Throwable throwable) {
         return RxJavaPlugins.onAssembly(new FlowableFromCallable<>(callable));
     }
 
+    /**
+     * Wraps a {@link CompletableSource} into a {@code Flowable}.
+     * <p>
+     * <img width="640" height="278" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromCompletable.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>This source doesn't produce any elements and effectively ignores downstream backpressure.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the target type
+     * @param completableSource the {@code CompletableSource} to convert from
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code completableSource} is {@code null}
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
+    public static <T> Flowable<T> fromCompletable(@NonNull CompletableSource completableSource) {
+        Objects.requireNonNull(completableSource, "completableSource is null");
+        return RxJavaPlugins.onAssembly(new FlowableFromCompletable<>(completableSource));
+    }
+
     /**
      * Converts a {@link Future} into a {@link Publisher}.
      * <p>
@@ -2157,6 +2215,94 @@ public static <T> Flowable<T> error(@NonNull Throwable throwable) {
         return RxJavaPlugins.onAssembly(new FlowableFromIterable<>(source));
     }
 
+    /**
+     * Returns a {@code Flowable} instance that when subscribed to, subscribes to the {@link MaybeSource} instance and
+     * emits {@code onSuccess} as a single item or forwards any {@code onComplete} or
+     * {@code onError} signal.
+     * <p>
+     * <img width="640" height="226" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromMaybe.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type of the {@code MaybeSource} element
+     * @param maybe the {@code MaybeSource} instance to subscribe to, not {@code null}
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code maybe} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public static <T> Flowable<T> fromMaybe(@NonNull MaybeSource<T> maybe) {
+        Objects.requireNonNull(maybe, "maybe is null");
+        return RxJavaPlugins.onAssembly(new MaybeToFlowable<>(maybe));
+    }
+
+    /**
+     * Converts the given {@link ObservableSource} into a {@code Flowable} by applying the specified backpressure strategy.
+     * <p>
+     * Marble diagrams for the various backpressure strategies are as follows:
+     * <ul>
+     * <li>{@link BackpressureStrategy#BUFFER}
+     * <p>
+     * <img width="640" height="264" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromObservable.buffer.png" alt="">
+     * </li>
+     * <li>{@link BackpressureStrategy#DROP}
+     * <p>
+     * <img width="640" height="374" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromObservable.drop.png" alt="">
+     * </li>
+     * <li>{@link BackpressureStrategy#LATEST}
+     * <p>
+     * <img width="640" height="284" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromObservable.latest.png" alt="">
+     * </li>
+     * <li>{@link BackpressureStrategy#ERROR}
+     * <p>
+     * <img width="640" height="365" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromObservable.error.png" alt="">
+     * </li>
+     * <li>{@link BackpressureStrategy#MISSING}
+     * <p>
+     * <img width="640" height="397" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromObservable.missing.png" alt="">
+     * </li>
+     * </ul>
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator applies the chosen backpressure strategy of {@link BackpressureStrategy} enum.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromObservable} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the element type of the source and resulting sequence
+     * @param source the {@code ObservableSource} to convert
+     * @param strategy the backpressure strategy to apply
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code source} or {@code strategy} is {@code null}
+     */
+    @BackpressureSupport(BackpressureKind.SPECIAL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> fromObservable(@NonNull ObservableSource<T> source, @NonNull BackpressureStrategy strategy) {
+        Objects.requireNonNull(source, "source is null");
+        Objects.requireNonNull(strategy, "strategy is null");
+        Flowable<T> f = new FlowableFromObservable<>(source);
+        switch (strategy) {
+            case DROP:
+                return f.onBackpressureDrop();
+            case LATEST:
+                return f.onBackpressureLatest();
+            case MISSING:
+                return f;
+            case ERROR:
+                return RxJavaPlugins.onAssembly(new FlowableOnBackpressureError<>(f));
+            default:
+                return f.onBackpressureBuffer();
+        }
+    }
+
     /**
      * Converts an arbitrary <em>Reactive Streams</em> {@link Publisher} into a {@code Flowable} if not already a
      * {@code Flowable}.
@@ -2198,6 +2344,65 @@ public static <T> Flowable<T> fromPublisher(@NonNull Publisher<@NonNull ? extend
         return RxJavaPlugins.onAssembly(new FlowableFromPublisher<>(publisher));
     }
 
+    /**
+     * Returns a {@code Flowable} instance that runs the given {@link Runnable} for each subscriber and
+     * emits either its exception or simply completes.
+     * <p>
+     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromRunnable.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>This source doesn't produce any elements and effectively ignores downstream backpressure.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromRunnable} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd> If the {@code Runnable} throws an exception, the respective {@link Throwable} is
+     *  delivered to the downstream via {@link Subscriber#onError(Throwable)},
+     *  except when the downstream has canceled the resulting {@code Flowable} source.
+     *  In this latter case, the {@code Throwable} is delivered to the global error handler via
+     *  {@link RxJavaPlugins#onError(Throwable)} as an {@link io.reactivex.rxjava3.exceptions.UndeliverableException UndeliverableException}.
+     *  </dd>
+     * </dl>
+     * @param <T> the target type
+     * @param run the {@code Runnable} to run for each subscriber
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code run} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
+    public static <T> Flowable<T> fromRunnable(@NonNull Runnable run) {
+        Objects.requireNonNull(run, "run is null");
+        return RxJavaPlugins.onAssembly(new FlowableFromRunnable<>(run));
+    }
+
+    /**
+     * Returns a {@code Flowable} instance that when subscribed to, subscribes to the {@link SingleSource} instance and
+     * emits {@code onSuccess} as a single item or forwards the {@code onError} signal.
+     * <p>
+     * <img width="640" height="341" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromSingle.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromSingle} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type of the {@code SingleSource} element
+     * @param source the {@code SingleSource} instance to subscribe to, not {@code null}
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code source} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public static <T> Flowable<T> fromSingle(@NonNull SingleSource<T> source) {
+        Objects.requireNonNull(source, "source is null");
+        return RxJavaPlugins.onAssembly(new SingleToFlowable<>(source));
+    }
+
     /**
      * Returns a {@code Flowable} that, when a {@link Subscriber} subscribes to it, invokes a supplier function you specify and then
      * emits the value returned from that function.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index a9435534f6..12ab3678e2 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -30,6 +30,7 @@
 import io.reactivex.rxjava3.internal.operators.flowable.*;
 import io.reactivex.rxjava3.internal.operators.maybe.*;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
+import io.reactivex.rxjava3.internal.operators.observable.ObservableElementAtMaybe;
 import io.reactivex.rxjava3.internal.util.ErrorMode;
 import io.reactivex.rxjava3.observers.TestObserver;
 import io.reactivex.rxjava3.plugins.RxJavaPlugins;
@@ -710,7 +711,7 @@ public static <T> Maybe<T> error(@NonNull Supplier<? extends Throwable> supplier
     }
 
     /**
-     * Returns a {@code Maybe} instance that runs the given {@link Action} for each subscriber and
+     * Returns a {@code Maybe} instance that runs the given {@link Action} for each observer and
      * emits either its exception or simply completes.
      * <p>
      * <img width="640" height="287" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromAction.png" alt="">
@@ -720,13 +721,13 @@ public static <T> Maybe<T> error(@NonNull Supplier<? extends Throwable> supplier
      *  <dt><b>Error handling:</b></dt>
      *  <dd> If the {@code Action} throws an exception, the respective {@link Throwable} is
      *  delivered to the downstream via {@link MaybeObserver#onError(Throwable)},
-     *  except when the downstream has disposed this {@code Maybe} source.
+     *  except when the downstream has disposed the resulting {@code Maybe} source.
      *  In this latter case, the {@code Throwable} is delivered to the global error handler via
      *  {@link RxJavaPlugins#onError(Throwable)} as an {@link io.reactivex.rxjava3.exceptions.UndeliverableException UndeliverableException}.
      *  </dd>
      * </dl>
      * @param <T> the target type
-     * @param action the {@code Action} to run for each subscriber
+     * @param action the {@code Action} to run for each observer
      * @return the new {@code Maybe} instance
      * @throws NullPointerException if {@code action} is {@code null}
      */
@@ -901,7 +902,57 @@ public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
     }
 
     /**
-     * Returns a {@code Maybe} instance that runs the given {@link Runnable} for each subscriber and
+     * Wraps an {@link ObservableSource} into a {@code Maybe} and emits the very first item
+     * or completes if the source is empty.
+     * <p>
+     * <img width="640" height="276" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromObservable.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromObservable} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the target type
+     * @param source the {@code ObservableSource} to convert from
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code source} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Maybe<T> fromObservable(@NonNull ObservableSource<T> source) {
+        Objects.requireNonNull(source, "source is null");
+        return RxJavaPlugins.onAssembly(new ObservableElementAtMaybe<>(source, 0L));
+    }
+
+    /**
+     * Wraps a {@link Publisher} into a {@code Maybe} and emits the very first item
+     * or completes if the source is empty.
+     * <p>
+     * <img width="640" height="309" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromPublisher.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator consumes the given {@code Publisher} in an unbounded manner
+     *  (requesting {@link Long#MAX_VALUE}) but cancels it after one item received.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromPublisher} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the target type
+     * @param source the {@code Publisher} to convert from
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code source} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
+    public static <T> Maybe<T> fromPublisher(@NonNull Publisher<T> source) {
+        Objects.requireNonNull(source, "source is null");
+        return RxJavaPlugins.onAssembly(new FlowableElementAtMaybePublisher<>(source, 0L));
+    }
+
+    /**
+     * Returns a {@code Maybe} instance that runs the given {@link Runnable} for each observer and
      * emits either its exception or simply completes.
      * <p>
      * <img width="640" height="287" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromRunnable.png" alt="">
@@ -910,7 +961,7 @@ public static <T> Maybe<T> fromSingle(@NonNull SingleSource<T> single) {
      *  <dd>{@code fromRunnable} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @param <T> the target type
-     * @param run the {@code Runnable} to run for each subscriber
+     * @param run the {@code Runnable} to run for each observer
      * @return the new {@code Maybe} instance
      * @throws NullPointerException if {@code run} is {@code null}
      */
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index f599ce0eeb..89de9dd63e 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -28,8 +28,10 @@
 import io.reactivex.rxjava3.internal.jdk8.*;
 import io.reactivex.rxjava3.internal.observers.*;
 import io.reactivex.rxjava3.internal.operators.flowable.*;
+import io.reactivex.rxjava3.internal.operators.maybe.MaybeToObservable;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
 import io.reactivex.rxjava3.internal.operators.observable.*;
+import io.reactivex.rxjava3.internal.operators.single.SingleToObservable;
 import io.reactivex.rxjava3.internal.util.*;
 import io.reactivex.rxjava3.observables.*;
 import io.reactivex.rxjava3.observers.*;
@@ -1734,6 +1736,36 @@ public static <T> Observable<T> error(@NonNull Throwable throwable) {
         return error(Functions.justSupplier(throwable));
     }
 
+    /**
+     * Returns an {@code Observable} instance that runs the given {@link Action} for each subscriber and
+     * emits either its exception or simply completes.
+     * <p>
+     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromAction.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromAction} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd> If the {@code Action} throws an exception, the respective {@link Throwable} is
+     *  delivered to the downstream via {@link Observer#onError(Throwable)},
+     *  except when the downstream has canceled the resulting {@code Observable} source.
+     *  In this latter case, the {@code Throwable} is delivered to the global error handler via
+     *  {@link RxJavaPlugins#onError(Throwable)} as an {@link io.reactivex.rxjava3.exceptions.UndeliverableException UndeliverableException}.
+     *  </dd>
+     * </dl>
+     * @param <T> the target type
+     * @param action the {@code Action} to run for each subscriber
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code action} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Observable<T> fromAction(@NonNull Action action) {
+        Objects.requireNonNull(action, "action is null");
+        return RxJavaPlugins.onAssembly(new ObservableFromAction<>(action));
+    }
+
     /**
      * Converts an array into an {@link ObservableSource} that emits the items in the array.
      * <p>
@@ -1804,6 +1836,27 @@ public static <T> Observable<T> fromCallable(@NonNull Callable<? extends T> call
         return RxJavaPlugins.onAssembly(new ObservableFromCallable<>(callable));
     }
 
+    /**
+     * Wraps a {@link CompletableSource} into an {@code Observable}.
+     * <p>
+     * <img width="640" height="278" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.fromCompletable.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the target type
+     * @param completableSource the {@code CompletableSource} to convert from
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code completableSource} is {@code null}
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Observable<T> fromCompletable(@NonNull CompletableSource completableSource) {
+        Objects.requireNonNull(completableSource, "completableSource is null");
+        return RxJavaPlugins.onAssembly(new ObservableFromCompletable<>(completableSource));
+    }
+
     /**
      * Converts a {@link Future} into an {@code Observable}.
      * <p>
@@ -1912,6 +1965,30 @@ public static <T> Observable<T> fromIterable(@NonNull Iterable<@NonNull ? extend
         return RxJavaPlugins.onAssembly(new ObservableFromIterable<>(source));
     }
 
+    /**
+     * Returns an {@code Observable} instance that when subscribed to, subscribes to the {@link MaybeSource} instance and
+     * emits {@code onSuccess} as a single item or forwards any {@code onComplete} or
+     * {@code onError} signal.
+     * <p>
+     * <img width="640" height="226" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.fromMaybe.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type of the {@code MaybeSource} element
+     * @param maybe the {@code MaybeSource} instance to subscribe to, not {@code null}
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code maybe} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Observable<T> fromMaybe(@NonNull MaybeSource<T> maybe) {
+        Objects.requireNonNull(maybe, "maybe is null");
+        return RxJavaPlugins.onAssembly(new MaybeToObservable<>(maybe));
+    }
+
     /**
      * Converts an arbitrary <em>Reactive Streams</em> {@link Publisher} into an {@code Observable}.
      * <p>
@@ -1949,6 +2026,59 @@ public static <T> Observable<T> fromPublisher(@NonNull Publisher<@NonNull ? exte
         return RxJavaPlugins.onAssembly(new ObservableFromPublisher<>(publisher));
     }
 
+    /**
+     * Returns an {@code Observable} instance that runs the given {@link Runnable} for each observer and
+     * emits either its exception or simply completes.
+     * <p>
+     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.fromRunnable.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromRunnable} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd> If the {@code Runnable} throws an exception, the respective {@link Throwable} is
+     *  delivered to the downstream via {@link Observer#onError(Throwable)},
+     *  except when the downstream has canceled the resulting {@code Observable} source.
+     *  In this latter case, the {@code Throwable} is delivered to the global error handler via
+     *  {@link RxJavaPlugins#onError(Throwable)} as an {@link io.reactivex.rxjava3.exceptions.UndeliverableException UndeliverableException}.
+     *  </dd>
+     * </dl>
+     * @param <T> the target type
+     * @param run the {@code Runnable} to run for each observer
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code run} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Observable<T> fromRunnable(@NonNull Runnable run) {
+        Objects.requireNonNull(run, "run is null");
+        return RxJavaPlugins.onAssembly(new ObservableFromRunnable<>(run));
+    }
+
+    /**
+     * Returns an {@code Observable} instance that when subscribed to, subscribes to the {@link SingleSource} instance and
+     * emits {@code onSuccess} as a single item or forwards the {@code onError} signal.
+     * <p>
+     * <img width="640" height="341" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.fromSingle.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromSingle} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type of the {@code SingleSource} element
+     * @param source the {@code SingleSource} instance to subscribe to, not {@code null}
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code source} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Observable<T> fromSingle(@NonNull SingleSource<T> source) {
+        Objects.requireNonNull(source, "source is null");
+        return RxJavaPlugins.onAssembly(new SingleToObservable<>(source));
+    }
+
     /**
      * Returns an {@code Observable} that, when an observer subscribes to it, invokes a supplier function you specify and then
      * emits the value returned from that function.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 3bfcd78a9c..a3b536b1f7 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -731,6 +731,56 @@ public static <T> Single<T> error(@NonNull Throwable throwable) {
         return toSingle(Flowable.fromFuture(future, timeout, unit));
     }
 
+    /**
+     * Returns a {@code Single} instance that when subscribed to, subscribes to the {@link MaybeSource} instance and
+     * emits {@code onSuccess} as a single item, turns an {@code onComplete} into {@link NoSuchElementException} error signal or
+     * forwards the {@code onError} signal.
+     * <p>
+     * <img width="640" height="241" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.fromMaybe.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type of the {@code MaybeSource} element
+     * @param maybe the {@code MaybeSource} instance to subscribe to, not {@code null}
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code maybe} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Single<T> fromMaybe(@NonNull MaybeSource<T> maybe) {
+        Objects.requireNonNull(maybe, "maybe is null");
+        return RxJavaPlugins.onAssembly(new MaybeToSingle<>(maybe, null));
+    }
+
+    /**
+     * Returns a {@code Single} instance that when subscribed to, subscribes to the {@link MaybeSource} instance and
+     * emits {@code onSuccess} as a single item, emits the {@code defaultItem} for an {@code onComplete} signal or
+     * forwards the {@code onError} signal.
+     * <p>
+     * <img width="640" height="353" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.fromMaybe.v.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code fromMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type of the {@code MaybeSource} element
+     * @param maybe the {@code MaybeSource} instance to subscribe to, not {@code null}
+     * @param defaultItem the item to signal if the current {@code MaybeSource} is empty
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code maybe} or {@code defaultItem} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Single<T> fromMaybe(@NonNull MaybeSource<T> maybe, @NonNull T defaultItem) {
+        Objects.requireNonNull(maybe, "maybe is null");
+        Objects.requireNonNull(defaultItem, "defaultItem is null");
+        return RxJavaPlugins.onAssembly(new MaybeToSingle<>(maybe, defaultItem));
+    }
+
     /**
      * Wraps a specific {@link Publisher} into a {@code Single} and signals its single element or error.
      * <p>
diff --git a/src/main/java/io/reactivex/rxjava3/internal/fuseable/AbstractEmptyQueueFuseable.java b/src/main/java/io/reactivex/rxjava3/internal/fuseable/AbstractEmptyQueueFuseable.java
new file mode 100644
index 0000000000..071db9fff8
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/fuseable/AbstractEmptyQueueFuseable.java
@@ -0,0 +1,76 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.fuseable;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+
+/**
+ * Represents an empty, async-only {@link QueueFuseable} instance.
+ *
+ * @param <T> the output value type
+ * @since 3.0.0
+ */
+public abstract class AbstractEmptyQueueFuseable<T>
+implements QueueSubscription<T>, QueueDisposable<T> {
+
+    @Override
+    public final int requestFusion(int mode) {
+        return mode & ASYNC;
+    }
+
+    @Override
+    public final boolean offer(@NonNull T value) {
+        throw new UnsupportedOperationException("Should not be called!");
+    }
+
+    @Override
+    public final boolean offer(@NonNull T v1, @NonNull T v2) {
+        throw new UnsupportedOperationException("Should not be called!");
+    }
+
+    @Override
+    public final T poll() throws Throwable {
+        return null; // always empty
+    }
+
+    @Override
+    public final boolean isEmpty() {
+        return true; // always empty
+    }
+
+    @Override
+    public final void clear() {
+        // always empty
+    }
+
+    @Override
+    public final void request(long n) {
+        // no items to request
+    }
+
+    @Override
+    public void cancel() {
+        // default No-op
+    }
+
+    @Override
+    public void dispose() {
+        // default No-op
+    }
+
+    @Override
+    public boolean isDisposed() {
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseable.java b/src/main/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseable.java
new file mode 100644
index 0000000000..8f9e12d3cb
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseable.java
@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.fuseable;
+
+/**
+ * Represents an empty, async-only {@link QueueFuseable} instance that tracks and exposes a
+ * canceled/disposed state.
+ *
+ * @param <T> the output value type
+ * @since 3.0.0
+ */
+public final class CancellableQueueFuseable<T>
+extends AbstractEmptyQueueFuseable<T> {
+
+    volatile boolean disposed;
+
+    @Override
+    public void cancel() {
+        disposed = true;
+    }
+
+    @Override
+    public void dispose() {
+        disposed = true;
+    }
+
+    @Override
+    public boolean isDisposed() {
+        return disposed;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/SubscriberCompletableObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/SubscriberCompletableObserver.java
deleted file mode 100644
index 2bbc5128d6..0000000000
--- a/src/main/java/io/reactivex/rxjava3/internal/observers/SubscriberCompletableObserver.java
+++ /dev/null
@@ -1,59 +0,0 @@
-/**
- * Copyright (c) 2016-present, RxJava Contributors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
- * compliance with the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software distributed under the License is
- * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
- * the License for the specific language governing permissions and limitations under the License.
- */
-
-package io.reactivex.rxjava3.internal.observers;
-
-import org.reactivestreams.*;
-
-import io.reactivex.rxjava3.core.CompletableObserver;
-import io.reactivex.rxjava3.disposables.Disposable;
-import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
-
-public final class SubscriberCompletableObserver<T> implements CompletableObserver, Subscription {
-    final Subscriber<? super T> subscriber;
-
-    Disposable upstream;
-
-    public SubscriberCompletableObserver(Subscriber<? super T> subscriber) {
-        this.subscriber = subscriber;
-    }
-
-    @Override
-    public void onComplete() {
-        subscriber.onComplete();
-    }
-
-    @Override
-    public void onError(Throwable e) {
-        subscriber.onError(e);
-    }
-
-    @Override
-    public void onSubscribe(Disposable d) {
-        if (DisposableHelper.validate(this.upstream, d)) {
-            this.upstream = d;
-
-            subscriber.onSubscribe(this);
-        }
-    }
-
-    @Override
-    public void request(long n) {
-        // ignored, no values emitted anyway
-    }
-
-    @Override
-    public void cancel() {
-        upstream.dispose();
-    }
-}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromAction.java b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromAction.java
index 4cd7fb479c..82bec67c92 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromAction.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromAction.java
@@ -31,19 +31,21 @@ public CompletableFromAction(Action run) {
     protected void subscribeActual(CompletableObserver observer) {
         Disposable d = Disposable.empty();
         observer.onSubscribe(d);
-        try {
-            run.run();
-        } catch (Throwable e) {
-            Exceptions.throwIfFatal(e);
+        if (!d.isDisposed()) {
+            try {
+                run.run();
+            } catch (Throwable e) {
+                Exceptions.throwIfFatal(e);
+                if (!d.isDisposed()) {
+                    observer.onError(e);
+                } else {
+                    RxJavaPlugins.onError(e);
+                }
+                return;
+            }
             if (!d.isDisposed()) {
-                observer.onError(e);
-            } else {
-                RxJavaPlugins.onError(e);
+                observer.onComplete();
             }
-            return;
-        }
-        if (!d.isDisposed()) {
-            observer.onComplete();
         }
     }
 
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnable.java
index e94d650310..60332d8db2 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnable.java
@@ -30,19 +30,21 @@ public CompletableFromRunnable(Runnable runnable) {
     protected void subscribeActual(CompletableObserver observer) {
         Disposable d = Disposable.empty();
         observer.onSubscribe(d);
-        try {
-            runnable.run();
-        } catch (Throwable e) {
-            Exceptions.throwIfFatal(e);
+        if (!d.isDisposed()) {
+            try {
+                runnable.run();
+            } catch (Throwable e) {
+                Exceptions.throwIfFatal(e);
+                if (!d.isDisposed()) {
+                    observer.onError(e);
+                } else {
+                    RxJavaPlugins.onError(e);
+                }
+                return;
+            }
             if (!d.isDisposed()) {
-                observer.onError(e);
-            } else {
-                RxJavaPlugins.onError(e);
+                observer.onComplete();
             }
-            return;
-        }
-        if (!d.isDisposed()) {
-            observer.onComplete();
         }
     }
 }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFlowable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFlowable.java
index 9ad0d0a8d8..9a6c0326a1 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFlowable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFlowable.java
@@ -16,7 +16,7 @@
 import org.reactivestreams.Subscriber;
 
 import io.reactivex.rxjava3.core.*;
-import io.reactivex.rxjava3.internal.observers.SubscriberCompletableObserver;
+import io.reactivex.rxjava3.internal.operators.flowable.FlowableFromCompletable;
 
 public final class CompletableToFlowable<T> extends Flowable<T> {
 
@@ -28,7 +28,6 @@ public CompletableToFlowable(CompletableSource source) {
 
     @Override
     protected void subscribeActual(Subscriber<? super T> s) {
-        SubscriberCompletableObserver<T> os = new SubscriberCompletableObserver<>(s);
-        source.subscribe(os);
+        source.subscribe(new FlowableFromCompletable.FromCompletableObserver<>(s));
     }
 }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservable.java
index 095a975dbf..84eea97c8d 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservable.java
@@ -14,9 +14,7 @@
 package io.reactivex.rxjava3.internal.operators.completable;
 
 import io.reactivex.rxjava3.core.*;
-import io.reactivex.rxjava3.disposables.Disposable;
-import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
-import io.reactivex.rxjava3.internal.observers.BasicQueueDisposable;
+import io.reactivex.rxjava3.internal.operators.observable.ObservableFromCompletable;
 
 /**
  * Wraps a Completable and exposes it as an Observable.
@@ -33,66 +31,6 @@ public CompletableToObservable(CompletableSource source) {
 
     @Override
     protected void subscribeActual(Observer<? super T> observer) {
-        source.subscribe(new ObserverCompletableObserver(observer));
-    }
-
-    static final class ObserverCompletableObserver extends BasicQueueDisposable<Void>
-    implements CompletableObserver {
-
-        final Observer<?> observer;
-
-        Disposable upstream;
-
-        ObserverCompletableObserver(Observer<?> observer) {
-            this.observer = observer;
-        }
-
-        @Override
-        public void onComplete() {
-            observer.onComplete();
-        }
-
-        @Override
-        public void onError(Throwable e) {
-            observer.onError(e);
-        }
-
-        @Override
-        public void onSubscribe(Disposable d) {
-            if (DisposableHelper.validate(upstream, d)) {
-                this.upstream = d;
-                observer.onSubscribe(this);
-            }
-        }
-
-        @Override
-        public int requestFusion(int mode) {
-            return mode & ASYNC;
-        }
-
-        @Override
-        public Void poll() {
-            return null; // always empty
-        }
-
-        @Override
-        public boolean isEmpty() {
-            return true;
-        }
-
-        @Override
-        public void clear() {
-            // always empty
-        }
-
-        @Override
-        public void dispose() {
-            upstream.dispose();
-        }
-
-        @Override
-        public boolean isDisposed() {
-            return upstream.isDisposed();
-        }
+        source.subscribe(new ObservableFromCompletable.FromCompletableObserver<>(observer));
     }
 }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableElementAtMaybePublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableElementAtMaybePublisher.java
new file mode 100644
index 0000000000..a474b03280
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableElementAtMaybePublisher.java
@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import org.reactivestreams.Publisher;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.internal.operators.flowable.FlowableElementAtMaybe.ElementAtSubscriber;
+
+/**
+ * Emits the indexth element from a Publisher as a Maybe.
+ *
+ * @param <T> the element type of the source
+ * @since 3.0.0
+ */
+public final class FlowableElementAtMaybePublisher<T> extends Maybe<T> {
+
+    final Publisher<T> source;
+
+    final long index;
+
+    public FlowableElementAtMaybePublisher(Publisher<T> source, long index) {
+        this.source = source;
+        this.index = index;
+    }
+
+    @Override
+    protected void subscribeActual(MaybeObserver<? super T> observer) {
+        source.subscribe(new ElementAtSubscriber<>(observer, index));
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromAction.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromAction.java
new file mode 100644
index 0000000000..2d683e7601
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromAction.java
@@ -0,0 +1,68 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import org.reactivestreams.Subscriber;
+
+import io.reactivex.rxjava3.core.Flowable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.fuseable.CancellableQueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Executes an {@link Action} and signals its exception or completes normally.
+ *
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class FlowableFromAction<T> extends Flowable<T> implements Supplier<T> {
+
+    final Action action;
+
+    public FlowableFromAction(Action action) {
+        this.action = action;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super T> subscriber) {
+        CancellableQueueFuseable<T> qs = new CancellableQueueFuseable<>();
+        subscriber.onSubscribe(qs);
+
+        if (!qs.isDisposed()) {
+
+            try {
+                action.run();
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                if (!qs.isDisposed()) {
+                    subscriber.onError(ex);
+                } else {
+                    RxJavaPlugins.onError(ex);
+                }
+                return;
+            }
+
+            if (!qs.isDisposed()) {
+                subscriber.onComplete();
+            }
+        }
+    }
+
+    @Override
+    public T get() throws Throwable {
+        action.run();
+        return null; // considered as onComplete()
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletable.java
new file mode 100644
index 0000000000..78b37325ca
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletable.java
@@ -0,0 +1,86 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import org.reactivestreams.Subscriber;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+import io.reactivex.rxjava3.internal.fuseable.*;
+
+/**
+ * Wrap a Completable into a Flowable.
+ *
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class FlowableFromCompletable<T> extends Flowable<T> implements HasUpstreamCompletableSource {
+
+    final CompletableSource source;
+
+    public FlowableFromCompletable(CompletableSource source) {
+        this.source = source;
+    }
+
+    @Override
+    public CompletableSource source() {
+        return source;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super T> observer) {
+        source.subscribe(new FromCompletableObserver<T>(observer));
+    }
+
+    public static final class FromCompletableObserver<T>
+    extends AbstractEmptyQueueFuseable<T>
+    implements CompletableObserver {
+
+        final Subscriber<? super T> downstream;
+
+        Disposable upstream;
+
+        public FromCompletableObserver(Subscriber<? super T> downstream) {
+            this.downstream = downstream;
+        }
+
+        @Override
+        public void cancel() {
+            upstream.dispose();
+            upstream = DisposableHelper.DISPOSED;
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onComplete() {
+            upstream = DisposableHelper.DISPOSED;
+            downstream.onComplete();
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            upstream = DisposableHelper.DISPOSED;
+            downstream.onError(e);
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservable.java
index 105c6b6ee2..459228f549 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservable.java
@@ -18,9 +18,10 @@
 import io.reactivex.rxjava3.disposables.Disposable;
 
 public final class FlowableFromObservable<T> extends Flowable<T> {
-    private final Observable<T> upstream;
 
-    public FlowableFromObservable(Observable<T> upstream) {
+    private final ObservableSource<T> upstream;
+
+    public FlowableFromObservable(ObservableSource<T> upstream) {
         this.upstream = upstream;
     }
 
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnable.java
new file mode 100644
index 0000000000..b163f1b7ee
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnable.java
@@ -0,0 +1,68 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import org.reactivestreams.Subscriber;
+
+import io.reactivex.rxjava3.core.Flowable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.Supplier;
+import io.reactivex.rxjava3.internal.fuseable.CancellableQueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Executes an {@link Runnable} and signals its exception or completes normally.
+ *
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class FlowableFromRunnable<T> extends Flowable<T> implements Supplier<T> {
+
+    final Runnable run;
+
+    public FlowableFromRunnable(Runnable run) {
+        this.run = run;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super T> subscriber) {
+        CancellableQueueFuseable<T> qs = new CancellableQueueFuseable<>();
+        subscriber.onSubscribe(qs);
+
+        if (!qs.isDisposed()) {
+
+            try {
+                run.run();
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                if (!qs.isDisposed()) {
+                    subscriber.onError(ex);
+                } else {
+                    RxJavaPlugins.onError(ex);
+                }
+                return;
+            }
+
+            if (!qs.isDisposed()) {
+                subscriber.onComplete();
+            }
+        }
+    }
+
+    @Override
+    public T get() throws Throwable {
+        run.run();
+        return null; // considered as onComplete()
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromCompletable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromCompletable.java
index bdbc2ec03b..5cb73e821c 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromCompletable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromCompletable.java
@@ -19,7 +19,7 @@
 import io.reactivex.rxjava3.internal.fuseable.HasUpstreamCompletableSource;
 
 /**
- * Wrap a Single into a Maybe.
+ * Wrap a Completable into a Maybe.
  *
  * @param <T> the value type
  */
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToSingle.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToSingle.java
index 3199521639..807b9cac51 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToSingle.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToSingle.java
@@ -22,7 +22,7 @@
 
 /**
  * Wraps a MaybeSource and exposes its onSuccess and onError signals and signals
- * NoSuchElementException for onComplete.
+ * NoSuchElementException for onComplete if {@code defaultValue} is null.
  *
  * @param <T> the value type
  */
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromAction.java b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromAction.java
new file mode 100644
index 0000000000..cccb5b5d38
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromAction.java
@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.fuseable.CancellableQueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Executes an {@link Action} and signals its exception or completes normally.
+ *
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class ObservableFromAction<T> extends Observable<T> implements Supplier<T> {
+
+    final Action action;
+
+    public ObservableFromAction(Action action) {
+        this.action = action;
+    }
+
+    @Override
+    protected void subscribeActual(Observer<? super T> observer) {
+        CancellableQueueFuseable<T> qs = new CancellableQueueFuseable<>();
+        observer.onSubscribe(qs);
+
+        if (!qs.isDisposed()) {
+
+            try {
+                action.run();
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                if (!qs.isDisposed()) {
+                    observer.onError(ex);
+                } else {
+                    RxJavaPlugins.onError(ex);
+                }
+                return;
+            }
+
+            if (!qs.isDisposed()) {
+                observer.onComplete();
+            }
+        }
+    }
+
+    @Override
+    public T get() throws Throwable {
+        action.run();
+        return null; // considered as onComplete()
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletable.java
new file mode 100644
index 0000000000..4748e6a625
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletable.java
@@ -0,0 +1,89 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+import io.reactivex.rxjava3.internal.fuseable.*;
+
+/**
+ * Wrap a Completable into an Observable.
+ *
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class ObservableFromCompletable<T> extends Observable<T> implements HasUpstreamCompletableSource {
+
+    final CompletableSource source;
+
+    public ObservableFromCompletable(CompletableSource source) {
+        this.source = source;
+    }
+
+    @Override
+    public CompletableSource source() {
+        return source;
+    }
+
+    @Override
+    protected void subscribeActual(Observer<? super T> observer) {
+        source.subscribe(new FromCompletableObserver<T>(observer));
+    }
+
+    public static final class FromCompletableObserver<T>
+    extends AbstractEmptyQueueFuseable<T>
+    implements CompletableObserver {
+
+        final Observer<? super T> downstream;
+
+        Disposable upstream;
+
+        public FromCompletableObserver(Observer<? super T> downstream) {
+            this.downstream = downstream;
+        }
+
+        @Override
+        public void dispose() {
+            upstream.dispose();
+            upstream = DisposableHelper.DISPOSED;
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onComplete() {
+            upstream = DisposableHelper.DISPOSED;
+            downstream.onComplete();
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            upstream = DisposableHelper.DISPOSED;
+            downstream.onError(e);
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnable.java
new file mode 100644
index 0000000000..0dc37a8993
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnable.java
@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.Supplier;
+import io.reactivex.rxjava3.internal.fuseable.CancellableQueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Executes an {@link Runnable} and signals its exception or completes normally.
+ *
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class ObservableFromRunnable<T> extends Observable<T> implements Supplier<T> {
+
+    final Runnable run;
+
+    public ObservableFromRunnable(Runnable run) {
+        this.run = run;
+    }
+
+    @Override
+    protected void subscribeActual(Observer<? super T> observer) {
+        CancellableQueueFuseable<T> qs = new CancellableQueueFuseable<>();
+        observer.onSubscribe(qs);
+
+        if (!qs.isDisposed()) {
+
+            try {
+                run.run();
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                if (!qs.isDisposed()) {
+                    observer.onError(ex);
+                } else {
+                    RxJavaPlugins.onError(ex);
+                }
+                return;
+            }
+
+            if (!qs.isDisposed()) {
+                observer.onComplete();
+            }
+        }
+    }
+
+    @Override
+    public T get() throws Throwable {
+        run.run();
+        return null; // considered as onComplete()
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java b/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java
new file mode 100644
index 0000000000..ed4718fd1c
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java
@@ -0,0 +1,75 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.fuseable;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class CancellableQueueFuseableTest {
+
+    @Test
+    public void offer() {
+        TestHelper.assertNoOffer(new CancellableQueueFuseable<>());
+    }
+
+    @Test
+    public void cancel() {
+        CancellableQueueFuseable<Object> qs = new CancellableQueueFuseable<>();
+
+        assertFalse(qs.isDisposed());
+
+        qs.cancel();
+
+        assertTrue(qs.isDisposed());
+
+        qs.cancel();
+
+        assertTrue(qs.isDisposed());
+    }
+
+    @Test
+    public void dispose() {
+        CancellableQueueFuseable<Object> qs = new CancellableQueueFuseable<>();
+
+        assertFalse(qs.isDisposed());
+
+        qs.dispose();
+
+        assertTrue(qs.isDisposed());
+
+        qs.dispose();
+
+        assertTrue(qs.isDisposed());
+    }
+
+    @Test
+    public void cancel2() {
+        AbstractEmptyQueueFuseable<Object> qs = new AbstractEmptyQueueFuseable<Object>() {};
+
+        assertFalse(qs.isDisposed());
+
+        qs.cancel();
+    }
+
+    @Test
+    public void dispose2() {
+        AbstractEmptyQueueFuseable<Object> qs = new AbstractEmptyQueueFuseable<Object>() {};
+
+        assertFalse(qs.isDisposed());
+
+        qs.dispose();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableAndThenCompletableabTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableAndThenCompletableabTest.java
index a98f3b5abb..051dd4e364 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableAndThenCompletableabTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableAndThenCompletableabTest.java
@@ -102,7 +102,7 @@ public void run() {
                 .andThen(Completable.complete())
                 .test(true)
                 .assertEmpty();
-        assertEquals(1, completableRunCount.get());
+        assertEquals(0, completableRunCount.get());
     }
 
     @Test
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromActionTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromActionTest.java
index 56354fc448..1f4df16f44 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromActionTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromActionTest.java
@@ -14,6 +14,7 @@
 package io.reactivex.rxjava3.internal.operators.completable;
 
 import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.*;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -108,7 +109,7 @@ public void run() throws Exception {
         .test(true)
         .assertEmpty();
 
-        assertEquals(1, calls.get());
+        assertEquals(0, calls.get());
     }
 
     @Test
@@ -124,6 +125,17 @@ public void run() throws Exception {
         .test(true)
         .assertEmpty();
 
-        assertEquals(1, calls.get());
+        assertEquals(0, calls.get());
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Action run = mock(Action.class);
+
+        Completable.fromAction(run)
+        .test(true)
+        .assertEmpty();
+
+        verify(run, never()).run();
     }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnableTest.java
index 5d6473077f..2559f09187 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnableTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableFromRunnableTest.java
@@ -14,6 +14,7 @@
 package io.reactivex.rxjava3.internal.operators.completable;
 
 import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.*;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -107,7 +108,7 @@ public void run() {
         .test(true)
         .assertEmpty();
 
-        assertEquals(1, calls.get());
+        assertEquals(0, calls.get());
     }
 
     @Test
@@ -123,6 +124,17 @@ public void run() {
         .test(true)
         .assertEmpty();
 
-        assertEquals(1, calls.get());
+        assertEquals(0, calls.get());
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Runnable run = mock(Runnable.class);
+
+        Completable.fromRunnable(run)
+        .test(true)
+        .assertEmpty();
+
+        verify(run, never()).run();
     }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservableTest.java
index f1bbda0353..96404e8167 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservableTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToObservableTest.java
@@ -13,16 +13,10 @@
 
 package io.reactivex.rxjava3.internal.operators.completable;
 
-import static org.junit.Assert.*;
-
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
-import io.reactivex.rxjava3.disposables.*;
 import io.reactivex.rxjava3.functions.Function;
-import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
-import io.reactivex.rxjava3.internal.operators.completable.CompletableToObservable.ObserverCompletableObserver;
-import io.reactivex.rxjava3.observers.TestObserver;
 import io.reactivex.rxjava3.testsupport.TestHelper;
 
 public class CompletableToObservableTest extends RxJavaTest {
@@ -37,36 +31,4 @@ public Observable<?> apply(Completable c) throws Exception {
         });
     }
 
-    @Test
-    public void fusion() throws Exception {
-        TestObserver<Void> to = new TestObserver<>();
-
-        ObserverCompletableObserver co = new ObserverCompletableObserver(to);
-
-        Disposable d = Disposable.empty();
-
-        co.onSubscribe(d);
-
-        assertEquals(QueueFuseable.NONE, co.requestFusion(QueueFuseable.SYNC));
-
-        assertEquals(QueueFuseable.ASYNC, co.requestFusion(QueueFuseable.ASYNC));
-
-        assertEquals(QueueFuseable.ASYNC, co.requestFusion(QueueFuseable.ANY));
-
-        assertTrue(co.isEmpty());
-
-        assertNull(co.poll());
-
-        co.clear();
-
-        assertFalse(co.isDisposed());
-
-        co.dispose();
-
-        assertTrue(d.isDisposed());
-
-        assertTrue(co.isDisposed());
-
-        TestHelper.assertNoOffer(co);
-    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromActionTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromActionTest.java
new file mode 100644
index 0000000000..b19a03159c
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromActionTest.java
@@ -0,0 +1,214 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class FlowableFromActionTest extends RxJavaTest {
+    @Test
+    public void fromAction() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Flowable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        })
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromActionTwice() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Action run = new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        };
+
+        Flowable.fromAction(run)
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+
+        Flowable.fromAction(run)
+            .test()
+            .assertResult();
+
+        assertEquals(2, atomicInteger.get());
+    }
+
+    @Test
+    public void fromActionInvokesLazy() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Flowable<Object> source = Flowable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        });
+
+        assertEquals(0, atomicInteger.get());
+
+        source
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromActionThrows() {
+        Flowable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                throw new UnsupportedOperationException();
+            }
+        })
+            .test()
+            .assertFailure(UnsupportedOperationException.class);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void callable() throws Throwable {
+        final int[] counter = { 0 };
+
+        Flowable<Void> m = Flowable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter[0]++;
+            }
+        });
+
+        assertTrue(m.getClass().toString(), m instanceof Supplier);
+
+        assertNull(((Supplier<Void>)m).get());
+
+        assertEquals(1, counter[0]);
+    }
+
+    @Test
+    public void noErrorLoss() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            final CountDownLatch cdl1 = new CountDownLatch(1);
+            final CountDownLatch cdl2 = new CountDownLatch(1);
+
+            TestSubscriber<Object> ts = Flowable.fromAction(new Action() {
+                @Override
+                public void run() throws Exception {
+                    cdl1.countDown();
+                    cdl2.await(5, TimeUnit.SECONDS);
+                }
+            }).subscribeOn(Schedulers.single()).test();
+
+            assertTrue(cdl1.await(5, TimeUnit.SECONDS));
+
+            ts.cancel();
+
+            int timeout = 10;
+
+            while (timeout-- > 0 && errors.isEmpty()) {
+                Thread.sleep(100);
+            }
+
+            TestHelper.assertUndeliverable(errors, 0, InterruptedException.class);
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Action run = mock(Action.class);
+
+        Flowable.fromAction(run)
+        .test(1L, true)
+        .assertEmpty();
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void cancelWhileRunning() {
+        final TestSubscriber<Object> ts = new TestSubscriber<>();
+
+        Flowable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                ts.cancel();
+            }
+        })
+        .subscribeWith(ts)
+        .assertEmpty();
+
+        assertTrue(ts.isCancelled());
+    }
+
+    @Test
+    public void asyncFused() throws Throwable {
+        TestSubscriberEx<Object> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Action action = mock(Action.class);
+
+        Flowable.fromAction(action)
+        .subscribe(ts);
+
+        ts.assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult();
+
+        verify(action).run();
+    }
+
+    @Test
+    public void syncFusedRejected() throws Throwable {
+        TestSubscriberEx<Object> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Action action = mock(Action.class);
+
+        Flowable.fromAction(action)
+        .subscribe(ts);
+
+        ts.assertFusionMode(QueueFuseable.NONE)
+        .assertResult();
+
+        verify(action).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletableTest.java
new file mode 100644
index 0000000000..47c0b815fb
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromCompletableTest.java
@@ -0,0 +1,196 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class FlowableFromCompletableTest extends RxJavaTest {
+    @Test
+    public void fromCompletable() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Flowable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        }))
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromCompletableTwice() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Action run = new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        };
+
+        Flowable.fromCompletable(Completable.fromAction(run))
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+
+        Flowable.fromCompletable(Completable.fromAction(run))
+            .test()
+            .assertResult();
+
+        assertEquals(2, atomicInteger.get());
+    }
+
+    @Test
+    public void fromCompletableInvokesLazy() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Flowable<Object> source = Flowable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        }));
+
+        assertEquals(0, atomicInteger.get());
+
+        source
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromCompletableThrows() {
+        Flowable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                throw new UnsupportedOperationException();
+            }
+        }))
+            .test()
+            .assertFailure(UnsupportedOperationException.class);
+    }
+
+    @Test
+    public void noErrorLoss() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            final CountDownLatch cdl1 = new CountDownLatch(1);
+            final CountDownLatch cdl2 = new CountDownLatch(1);
+
+            TestSubscriber<Object> ts = Flowable.fromCompletable(Completable.fromAction(new Action() {
+                @Override
+                public void run() throws Exception {
+                    cdl1.countDown();
+                    cdl2.await(5, TimeUnit.SECONDS);
+                }
+            }))
+            .subscribeOn(Schedulers.single()).test();
+
+            assertTrue(cdl1.await(5, TimeUnit.SECONDS));
+
+            ts.cancel();
+
+            int timeout = 10;
+
+            while (timeout-- > 0 && errors.isEmpty()) {
+                Thread.sleep(100);
+            }
+
+            TestHelper.assertUndeliverable(errors, 0, InterruptedException.class);
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Action run = mock(Action.class);
+
+        Flowable.fromCompletable(Completable.fromAction(run))
+        .test(1L, true)
+        .assertEmpty();
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void cancelWhileRunning() {
+        final TestSubscriber<Object> ts = new TestSubscriber<>();
+
+        Flowable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                ts.cancel();
+            }
+        }))
+        .subscribeWith(ts)
+        .assertEmpty();
+
+        assertTrue(ts.isCancelled());
+    }
+
+    @Test
+    public void asyncFused() throws Throwable {
+        TestSubscriberEx<Object> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Action action = mock(Action.class);
+
+        Flowable.fromCompletable(Completable.fromAction(action))
+        .subscribe(ts);
+
+        ts.assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult();
+
+        verify(action).run();
+    }
+
+    @Test
+    public void syncFusedRejected() throws Throwable {
+        TestSubscriberEx<Object> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Action action = mock(Action.class);
+
+        Flowable.fromCompletable(Completable.fromAction(action))
+        .subscribe(ts);
+
+        ts.assertFusionMode(QueueFuseable.NONE)
+        .assertResult();
+
+        verify(action).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromMaybeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromMaybeTest.java
new file mode 100644
index 0000000000..5eca34f9cb
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromMaybeTest.java
@@ -0,0 +1,93 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+import io.reactivex.rxjava3.testsupport.TestSubscriberEx;
+
+public class FlowableFromMaybeTest extends RxJavaTest {
+
+    @Test
+    public void success() {
+        Flowable.fromMaybe(Maybe.just(1).hide())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void empty() {
+        Flowable.fromMaybe(Maybe.empty().hide())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void error() {
+        Flowable.fromMaybe(Maybe.error(new TestException()).hide())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void cancelComposes() {
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        TestSubscriber<Integer> ts = Flowable.fromMaybe(ms)
+        .test();
+
+        ts.assertEmpty();
+
+        assertTrue(ms.hasObservers());
+
+        ts.cancel();
+
+        assertFalse(ms.hasObservers());
+    }
+
+    @Test
+    public void asyncFusion() {
+        TestSubscriberEx<Integer> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Flowable.fromMaybe(Maybe.just(1))
+        .subscribe(ts);
+
+        ts
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult(1);
+    }
+
+    @Test
+    public void syncFusionRejected() {
+        TestSubscriberEx<Integer> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Flowable.fromMaybe(Maybe.just(1))
+        .subscribe(ts);
+
+        ts
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.NONE)
+        .assertResult(1);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservableTest.java
index 5689eadf49..0ef64d192c 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservableTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromObservableTest.java
@@ -32,4 +32,14 @@ public void error() {
         .test()
         .assertFailure(TestException.class);
     }
+
+    @Test
+    public void all() {
+        for (BackpressureStrategy mode : BackpressureStrategy.values()) {
+            Flowable.fromObservable(Observable.range(1, 5), mode)
+            .test()
+            .withTag("mode: " + mode)
+            .assertResult(1, 2, 3, 4, 5);
+        }
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnableTest.java
new file mode 100644
index 0000000000..f133c8fb99
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromRunnableTest.java
@@ -0,0 +1,220 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Supplier;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class FlowableFromRunnableTest extends RxJavaTest {
+    @Test
+    public void fromRunnable() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Flowable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                atomicInteger.incrementAndGet();
+            }
+        })
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromRunnableTwice() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Runnable run = new Runnable() {
+            @Override
+            public void run() {
+                atomicInteger.incrementAndGet();
+            }
+        };
+
+        Flowable.fromRunnable(run)
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+
+        Flowable.fromRunnable(run)
+            .test()
+            .assertResult();
+
+        assertEquals(2, atomicInteger.get());
+    }
+
+    @Test
+    public void fromRunnableInvokesLazy() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Flowable<Object> source = Flowable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                atomicInteger.incrementAndGet();
+            }
+        });
+
+        assertEquals(0, atomicInteger.get());
+
+        source
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromRunnableThrows() {
+        Flowable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                throw new UnsupportedOperationException();
+            }
+        })
+            .test()
+            .assertFailure(UnsupportedOperationException.class);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void callable() throws Throwable {
+        final int[] counter = { 0 };
+
+        Flowable<Void> m = Flowable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                counter[0]++;
+            }
+        });
+
+        assertTrue(m.getClass().toString(), m instanceof Supplier);
+
+        assertNull(((Supplier<Void>)m).get());
+
+        assertEquals(1, counter[0]);
+    }
+
+    @Test
+    public void noErrorLoss() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            final CountDownLatch cdl1 = new CountDownLatch(1);
+            final CountDownLatch cdl2 = new CountDownLatch(1);
+
+            TestSubscriber<Object> ts = Flowable.fromRunnable(new Runnable() {
+                @Override
+                public void run() {
+                    cdl1.countDown();
+                    try {
+                        cdl2.await(5, TimeUnit.SECONDS);
+                    } catch (InterruptedException e) {
+                        e.printStackTrace();
+                        throw new TestException(e);
+                    }
+                }
+            }).subscribeOn(Schedulers.single()).test();
+
+            assertTrue(cdl1.await(5, TimeUnit.SECONDS));
+
+            ts.cancel();
+
+            int timeout = 10;
+
+            while (timeout-- > 0 && errors.isEmpty()) {
+                Thread.sleep(100);
+            }
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run)
+        .test(1L, true)
+        .assertEmpty();
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void cancelWhileRunning() {
+        final TestSubscriber<Object> ts = new TestSubscriber<>();
+
+        Flowable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                ts.cancel();
+            }
+        })
+        .subscribeWith(ts)
+        .assertEmpty();
+
+        assertTrue(ts.isCancelled());
+    }
+
+    @Test
+    public void asyncFused() throws Throwable {
+        TestSubscriberEx<Object> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Runnable action = mock(Runnable.class);
+
+        Flowable.fromRunnable(action)
+        .subscribe(ts);
+
+        ts.assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult();
+
+        verify(action).run();
+    }
+
+    @Test
+    public void syncFusedRejected() throws Throwable {
+        TestSubscriberEx<Object> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Runnable action = mock(Runnable.class);
+
+        Flowable.fromRunnable(action)
+        .subscribe(ts);
+
+        ts.assertFusionMode(QueueFuseable.NONE)
+        .assertResult();
+
+        verify(action).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromSingleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromSingleTest.java
new file mode 100644
index 0000000000..01f6b1661f
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFromSingleTest.java
@@ -0,0 +1,86 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.subscribers.TestSubscriber;
+import io.reactivex.rxjava3.testsupport.TestSubscriberEx;
+
+public class FlowableFromSingleTest extends RxJavaTest {
+
+    @Test
+    public void success() {
+        Flowable.fromSingle(Single.just(1).hide())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void error() {
+        Flowable.fromSingle(Single.error(new TestException()).hide())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void cancelComposes() {
+        SingleSubject<Integer> ms = SingleSubject.create();
+
+        TestSubscriber<Integer> ts = Flowable.fromSingle(ms)
+        .test();
+
+        ts.assertEmpty();
+
+        assertTrue(ms.hasObservers());
+
+        ts.cancel();
+
+        assertFalse(ms.hasObservers());
+    }
+
+    @Test
+    public void asyncFusion() {
+        TestSubscriberEx<Integer> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Flowable.fromSingle(Single.just(1))
+        .subscribe(ts);
+
+        ts
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult(1);
+    }
+
+    @Test
+    public void syncFusionRejected() {
+        TestSubscriberEx<Integer> ts = new TestSubscriberEx<>();
+        ts.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Flowable.fromSingle(Single.just(1))
+        .subscribe(ts);
+
+        ts
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.NONE)
+        .assertResult(1);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromObservableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromObservableTest.java
new file mode 100644
index 0000000000..de2039a4d0
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromObservableTest.java
@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class MaybeFromObservableTest extends RxJavaTest {
+
+    @Test
+    public void empty() {
+        Maybe.fromObservable(Observable.empty().hide())
+            .test()
+            .assertResult();
+    }
+
+    @Test
+    public void just() {
+        Maybe.fromObservable(Observable.just(1).hide())
+            .test()
+            .assertResult(1);
+    }
+
+    @Test
+    public void range() {
+        Maybe.fromObservable(Observable.range(1, 5).hide())
+            .test()
+            .assertResult(1);
+    }
+
+    @Test
+    public void error() {
+        Maybe.fromObservable(Observable.error(new TestException()).hide())
+            .test()
+            .assertFailure(TestException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromPubisherTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromPubisherTest.java
new file mode 100644
index 0000000000..bcbef3dc9f
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFromPubisherTest.java
@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class MaybeFromPubisherTest extends RxJavaTest {
+
+    @Test
+    public void empty() {
+        Maybe.fromPublisher(Flowable.empty().hide())
+            .test()
+            .assertResult();
+    }
+
+    @Test
+    public void just() {
+        Maybe.fromPublisher(Flowable.just(1).hide())
+            .test()
+            .assertResult(1);
+    }
+
+    @Test
+    public void range() {
+        Maybe.fromPublisher(Flowable.range(1, 5).hide())
+            .test()
+            .assertResult(1);
+    }
+
+    @Test
+    public void error() {
+        Maybe.fromPublisher(Flowable.error(new TestException()).hide())
+            .test()
+            .assertFailure(TestException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromActionTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromActionTest.java
new file mode 100644
index 0000000000..2b6d80896a
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromActionTest.java
@@ -0,0 +1,214 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class ObservableFromActionTest extends RxJavaTest {
+    @Test
+    public void fromAction() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Observable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        })
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromActionTwice() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Action run = new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        };
+
+        Observable.fromAction(run)
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+
+        Observable.fromAction(run)
+            .test()
+            .assertResult();
+
+        assertEquals(2, atomicInteger.get());
+    }
+
+    @Test
+    public void fromActionInvokesLazy() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Observable<Object> source = Observable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        });
+
+        assertEquals(0, atomicInteger.get());
+
+        source
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromActionThrows() {
+        Observable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                throw new UnsupportedOperationException();
+            }
+        })
+            .test()
+            .assertFailure(UnsupportedOperationException.class);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void callable() throws Throwable {
+        final int[] counter = { 0 };
+
+        Observable<Void> m = Observable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter[0]++;
+            }
+        });
+
+        assertTrue(m.getClass().toString(), m instanceof Supplier);
+
+        assertNull(((Supplier<Void>)m).get());
+
+        assertEquals(1, counter[0]);
+    }
+
+    @Test
+    public void noErrorLoss() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            final CountDownLatch cdl1 = new CountDownLatch(1);
+            final CountDownLatch cdl2 = new CountDownLatch(1);
+
+            TestObserver<Object> to = Observable.fromAction(new Action() {
+                @Override
+                public void run() throws Exception {
+                    cdl1.countDown();
+                    cdl2.await(5, TimeUnit.SECONDS);
+                }
+            }).subscribeOn(Schedulers.single()).test();
+
+            assertTrue(cdl1.await(5, TimeUnit.SECONDS));
+
+            to.dispose();
+
+            int timeout = 10;
+
+            while (timeout-- > 0 && errors.isEmpty()) {
+                Thread.sleep(100);
+            }
+
+            TestHelper.assertUndeliverable(errors, 0, InterruptedException.class);
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Action run = mock(Action.class);
+
+        Observable.fromAction(run)
+        .test(true)
+        .assertEmpty();
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void cancelWhileRunning() {
+        final TestObserver<Object> to = new TestObserver<>();
+
+        Observable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                to.dispose();
+            }
+        })
+        .subscribeWith(to)
+        .assertEmpty();
+
+        assertTrue(to.isDisposed());
+    }
+
+    @Test
+    public void asyncFused() throws Throwable {
+        TestObserverEx<Object> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Action action = mock(Action.class);
+
+        Observable.fromAction(action)
+        .subscribe(to);
+
+        to.assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult();
+
+        verify(action).run();
+    }
+
+    @Test
+    public void syncFusedRejected() throws Throwable {
+        TestObserverEx<Object> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Action action = mock(Action.class);
+
+        Observable.fromAction(action)
+        .subscribe(to);
+
+        to.assertFusionMode(QueueFuseable.NONE)
+        .assertResult();
+
+        verify(action).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletableTest.java
new file mode 100644
index 0000000000..6cdc0108d6
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromCompletableTest.java
@@ -0,0 +1,195 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class ObservableFromCompletableTest extends RxJavaTest {
+    @Test
+    public void fromCompletable() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Observable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        }))
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromCompletableTwice() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Action run = new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        };
+
+        Observable.fromCompletable(Completable.fromAction(run))
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+
+        Observable.fromCompletable(Completable.fromAction(run))
+            .test()
+            .assertResult();
+
+        assertEquals(2, atomicInteger.get());
+    }
+
+    @Test
+    public void fromCompletableInvokesLazy() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Observable<Object> source = Observable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                atomicInteger.incrementAndGet();
+            }
+        }));
+
+        assertEquals(0, atomicInteger.get());
+
+        source
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromCompletableThrows() {
+        Observable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                throw new UnsupportedOperationException();
+            }
+        }))
+            .test()
+            .assertFailure(UnsupportedOperationException.class);
+    }
+
+    @Test
+    public void noErrorLoss() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            final CountDownLatch cdl1 = new CountDownLatch(1);
+            final CountDownLatch cdl2 = new CountDownLatch(1);
+
+            TestObserver<Object> to = Observable.fromCompletable(Completable.fromAction(new Action() {
+                @Override
+                public void run() throws Exception {
+                    cdl1.countDown();
+                    cdl2.await(5, TimeUnit.SECONDS);
+                }
+            })).subscribeOn(Schedulers.single()).test();
+
+            assertTrue(cdl1.await(5, TimeUnit.SECONDS));
+
+            to.dispose();
+
+            int timeout = 10;
+
+            while (timeout-- > 0 && errors.isEmpty()) {
+                Thread.sleep(100);
+            }
+
+            TestHelper.assertUndeliverable(errors, 0, InterruptedException.class);
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Action run = mock(Action.class);
+
+        Observable.fromCompletable(Completable.fromAction(run))
+        .test(true)
+        .assertEmpty();
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void cancelWhileRunning() {
+        final TestObserver<Object> to = new TestObserver<>();
+
+        Observable.fromCompletable(Completable.fromAction(new Action() {
+            @Override
+            public void run() throws Exception {
+                to.dispose();
+            }
+        }))
+        .subscribeWith(to)
+        .assertEmpty();
+
+        assertTrue(to.isDisposed());
+    }
+
+    @Test
+    public void asyncFused() throws Throwable {
+        TestObserverEx<Object> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Action action = mock(Action.class);
+
+        Observable.fromCompletable(Completable.fromAction(action))
+        .subscribe(to);
+
+        to.assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult();
+
+        verify(action).run();
+    }
+
+    @Test
+    public void syncFusedRejected() throws Throwable {
+        TestObserverEx<Object> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Action action = mock(Action.class);
+
+        Observable.fromCompletable(Completable.fromAction(action))
+        .subscribe(to);
+
+        to.assertFusionMode(QueueFuseable.NONE)
+        .assertResult();
+
+        verify(action).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromMaybeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromMaybeTest.java
new file mode 100644
index 0000000000..185b363d57
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromMaybeTest.java
@@ -0,0 +1,93 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.testsupport.TestObserverEx;
+
+public class ObservableFromMaybeTest extends RxJavaTest {
+
+    @Test
+    public void success() {
+        Observable.fromMaybe(Maybe.just(1).hide())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void empty() {
+        Observable.fromMaybe(Maybe.empty().hide())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void error() {
+        Observable.fromMaybe(Maybe.error(new TestException()).hide())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void cancelComposes() {
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        TestObserver<Integer> to = Observable.fromMaybe(ms)
+        .test();
+
+        to.assertEmpty();
+
+        assertTrue(ms.hasObservers());
+
+        to.dispose();
+
+        assertFalse(ms.hasObservers());
+    }
+
+    @Test
+    public void asyncFusion() {
+        TestObserverEx<Integer> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Observable.fromMaybe(Maybe.just(1))
+        .subscribe(to);
+
+        to
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult(1);
+    }
+
+    @Test
+    public void syncFusionRejected() {
+        TestObserverEx<Integer> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Observable.fromMaybe(Maybe.just(1))
+        .subscribe(to);
+
+        to
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.NONE)
+        .assertResult(1);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnableTest.java
new file mode 100644
index 0000000000..834abbd978
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromRunnableTest.java
@@ -0,0 +1,220 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Supplier;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class ObservableFromRunnableTest extends RxJavaTest {
+    @Test
+    public void fromRunnable() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Observable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                atomicInteger.incrementAndGet();
+            }
+        })
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromRunnableTwice() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Runnable run = new Runnable() {
+            @Override
+            public void run() {
+                atomicInteger.incrementAndGet();
+            }
+        };
+
+        Observable.fromRunnable(run)
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+
+        Observable.fromRunnable(run)
+            .test()
+            .assertResult();
+
+        assertEquals(2, atomicInteger.get());
+    }
+
+    @Test
+    public void fromRunnableInvokesLazy() {
+        final AtomicInteger atomicInteger = new AtomicInteger();
+
+        Observable<Object> source = Observable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                atomicInteger.incrementAndGet();
+            }
+        });
+
+        assertEquals(0, atomicInteger.get());
+
+        source
+            .test()
+            .assertResult();
+
+        assertEquals(1, atomicInteger.get());
+    }
+
+    @Test
+    public void fromRunnableThrows() {
+        Observable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                throw new UnsupportedOperationException();
+            }
+        })
+            .test()
+            .assertFailure(UnsupportedOperationException.class);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void callable() throws Throwable {
+        final int[] counter = { 0 };
+
+        Observable<Void> m = Observable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                counter[0]++;
+            }
+        });
+
+        assertTrue(m.getClass().toString(), m instanceof Supplier);
+
+        assertNull(((Supplier<Void>)m).get());
+
+        assertEquals(1, counter[0]);
+    }
+
+    @Test
+    public void noErrorLoss() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            final CountDownLatch cdl1 = new CountDownLatch(1);
+            final CountDownLatch cdl2 = new CountDownLatch(1);
+
+            TestObserver<Object> to = Observable.fromRunnable(new Runnable() {
+                @Override
+                public void run() {
+                    cdl1.countDown();
+                    try {
+                        cdl2.await(5, TimeUnit.SECONDS);
+                    } catch (InterruptedException e) {
+                        e.printStackTrace();
+                        throw new TestException(e);
+                    }
+                }
+            }).subscribeOn(Schedulers.single()).test();
+
+            assertTrue(cdl1.await(5, TimeUnit.SECONDS));
+
+            to.dispose();
+
+            int timeout = 10;
+
+            while (timeout-- > 0 && errors.isEmpty()) {
+                Thread.sleep(100);
+            }
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void disposedUpfront() throws Throwable {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run)
+        .test(true)
+        .assertEmpty();
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void cancelWhileRunning() {
+        final TestObserver<Object> to = new TestObserver<>();
+
+        Observable.fromRunnable(new Runnable() {
+            @Override
+            public void run() {
+                to.dispose();
+            }
+        })
+        .subscribeWith(to)
+        .assertEmpty();
+
+        assertTrue(to.isDisposed());
+    }
+
+    @Test
+    public void asyncFused() throws Throwable {
+        TestObserverEx<Object> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Runnable action = mock(Runnable.class);
+
+        Observable.fromRunnable(action)
+        .subscribe(to);
+
+        to.assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult();
+
+        verify(action).run();
+    }
+
+    @Test
+    public void syncFusedRejected() throws Throwable {
+        TestObserverEx<Object> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Runnable action = mock(Runnable.class);
+
+        Observable.fromRunnable(action)
+        .subscribe(to);
+
+        to.assertFusionMode(QueueFuseable.NONE)
+        .assertResult();
+
+        verify(action).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromSingleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromSingleTest.java
new file mode 100644
index 0000000000..d77498cea8
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableFromSingleTest.java
@@ -0,0 +1,86 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.internal.fuseable.QueueFuseable;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.testsupport.TestObserverEx;
+
+public class ObservableFromSingleTest extends RxJavaTest {
+
+    @Test
+    public void success() {
+        Observable.fromSingle(Single.just(1).hide())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void error() {
+        Observable.fromSingle(Single.error(new TestException()).hide())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void cancelComposes() {
+        SingleSubject<Integer> ms = SingleSubject.create();
+
+        TestObserver<Integer> to = Observable.fromSingle(ms)
+        .test();
+
+        to.assertEmpty();
+
+        assertTrue(ms.hasObservers());
+
+        to.dispose();
+
+        assertFalse(ms.hasObservers());
+    }
+
+    @Test
+    public void asyncFusion() {
+        TestObserverEx<Integer> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.ASYNC);
+
+        Observable.fromSingle(Single.just(1))
+        .subscribe(to);
+
+        to
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.ASYNC)
+        .assertResult(1);
+    }
+
+    @Test
+    public void syncFusionRejected() {
+        TestObserverEx<Integer> to = new TestObserverEx<>();
+        to.setInitialFusionMode(QueueFuseable.SYNC);
+
+        Observable.fromSingle(Single.just(1))
+        .subscribe(to);
+
+        to
+        .assertFuseable()
+        .assertFusionMode(QueueFuseable.NONE)
+        .assertResult(1);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFromMaybeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFromMaybeTest.java
new file mode 100644
index 0000000000..50eed426a7
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFromMaybeTest.java
@@ -0,0 +1,72 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.*;
+
+import java.util.NoSuchElementException;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+
+public class SingleFromMaybeTest extends RxJavaTest {
+
+    @Test
+    public void success() {
+        Single.fromMaybe(Maybe.just(1).hide())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void empty() {
+        Single.fromMaybe(Maybe.empty().hide())
+        .test()
+        .assertFailure(NoSuchElementException.class);
+    }
+
+    @Test
+    public void emptyDefault() {
+        Single.fromMaybe(Maybe.empty().hide(), 1)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void error() {
+        Single.fromMaybe(Maybe.error(new TestException()).hide())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void cancelComposes() {
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        TestObserver<Integer> to = Single.fromMaybe(ms)
+        .test();
+
+        to.assertEmpty();
+
+        assertTrue(ms.hasObservers());
+
+        to.dispose();
+
+        assertFalse(ms.hasObservers());
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index d99202adef..60b5a11fb6 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -83,6 +83,7 @@ public static void main(String[] args) throws IOException {
             Map<String, Integer> notesMap = new HashMap<>();
             List<String> notesList = new ArrayList<>();
             List<String> tbdList = new ArrayList<>();
+            int[] counters = new int[CLASSES.length];
 
             for (String operatorName : sortedOperators) {
                 out.print("<a name='");
@@ -90,9 +91,11 @@ public static void main(String[] args) throws IOException {
                 out.print("'></a>`");
                 out.print(operatorName);
                 out.print("`|");
+                int m = 0;
                 for (Class<?> clazz : CLASSES) {
                     if (operatorMap.get(clazz).contains(operatorName)) {
                         out.print(PRESENT);
+                        counters[m]++;
                     } else {
                         String notes = findNotes(clazz.getSimpleName(), operatorName);
                         if (notes != null) {
@@ -116,9 +119,19 @@ public static void main(String[] args) throws IOException {
                         }
                     }
                     out.print("|");
+                    m++;
                 }
                 out.println();
             }
+            out.print("<a name='total'></a>**");
+            out.print(sortedOperators.size());
+            out.print(" operators** |");
+            for (int m = 0; m < counters.length; m++) {
+                out.print(" **");
+                out.print(counters[m]);
+                out.print("** |");
+            }
+            out.println();
 
             if (!notesList.isEmpty()) {
                 out.println();
@@ -316,6 +329,7 @@ static String findNotes(String clazzName, String operatorName) {
             "    C flattenStreamAsObservable            Always empty thus no items to map.",
             "  MSC forEach                              Use [`subscribe()`](#subscribe).",
             "  MSC forEachWhile                         Use [`subscribe()`](#subscribe).",
+            "   S  fromAction                           Never empty.",
             "  M   fromArray                            At most one item. Use [`just()`](#just) or [`empty()`](#empty).",
             "   S  fromArray                            Always one item. Use [`just()`](#just).",
             "    C fromArray                            Always empty. Use [`complete()`](#complete).",
@@ -328,6 +342,7 @@ static String findNotes(String clazzName, String operatorName) {
             " O    fromObservable                       Use [`wrap()`](#wrap).",
             "   S  fromOptional                         Always one item. Use [`just()`](#just).",
             "    C fromOptional                         Always empty. Use [`complete()`](#complete).",
+            "   S  fromRunnable                         Never empty.",
             "   S  fromSingle                           Use [`wrap()`](#wrap).",
             "  M   fromStream                           At most one item. Use [`just()`](#just) or [`empty()`](#empty).",
             "   S  fromStream                           Always one item. Use [`just()`](#just).",
diff --git a/src/test/java/io/reactivex/rxjava3/validators/InternalWrongNaming.java b/src/test/java/io/reactivex/rxjava3/validators/InternalWrongNaming.java
index 14d937502f..a1ad772f05 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/InternalWrongNaming.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/InternalWrongNaming.java
@@ -62,7 +62,7 @@ static void checkInternalOperatorNaming(String baseClassName, String consumerCla
                         fail.append("java.lang.RuntimeException: " + g.getName() + " mentions " + consumerClassName)
                         .append("\r\n at io.reactivex.internal.operators.")
                         .append(baseClassName.toLowerCase()).append(".").append(g.getName().replace(".java", ""))
-                        .append(" (").append(g.getName()).append(":").append(i + 1).append(")\r\n\r\n");
+                        .append(".method(").append(g.getName()).append(":").append(i + 1).append(")\r\n\r\n");
 
                         count++;
                     }
@@ -170,6 +170,9 @@ public void flowableNoObserver() throws Exception {
                 "FlowableCountSingle",
                 "FlowableElementAtMaybe",
                 "FlowableElementAtSingle",
+                "FlowableElementAtMaybePublisher",
+                "FlowableElementAtSinglePublisher",
+                "FlowableFromCompletable",
                 "FlowableSingleSingle",
                 "FlowableSingleMaybe",
                 "FlowableLastMaybe",

From d5449b2fd63c73dea06fbbd5d584bab7b9cfde5d Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sun, 26 Jan 2020 10:25:53 +0100
Subject: [PATCH 20/37] 3.x: Add timeInterval & timestamp to M/S (#6874)

* 3.x: Add timeInterval & timestamp to M/S

* Fix null not allowed in Timed

* Fix Timed coverage
---
 docs/Operator-Matrix.md                       |  46 ++--
 .../java/io/reactivex/rxjava3/core/Maybe.java | 228 +++++++++++++++++-
 .../io/reactivex/rxjava3/core/Single.java     | 228 +++++++++++++++++-
 .../operators/maybe/MaybeTimeInterval.java    | 105 ++++++++
 .../operators/single/SingleTimeInterval.java  | 100 ++++++++
 .../reactivex/rxjava3/schedulers/Timed.java   |   6 +-
 .../maybe/MaybeTimeIntervalTest.java          | 111 +++++++++
 .../operators/maybe/MaybeTimestampTest.java   | 111 +++++++++
 .../single/SingleTimeIntervalTest.java        | 103 ++++++++
 .../operators/single/SingleTimestampTest.java | 103 ++++++++
 .../util/OperatorMatrixGenerator.java         |   1 +
 .../rxjava3/schedulers/TimedTest.java         |   2 +-
 .../rxjava3/validators/JavadocWording.java    |   4 +-
 13 files changed, 1114 insertions(+), 34 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeInterval.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeInterval.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeIntervalTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimestampTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeIntervalTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimestampTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 81e1f7878d..10427533cc 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -58,7 +58,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='defer'></a>`defer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delay'></a>`delay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delaySubscription'></a>`delaySubscription`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
@@ -212,10 +212,10 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='timeout'></a>`timeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='timer'></a>`timer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -237,7 +237,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([108](#notes-108))</sup>|
 <a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([109](#notes-109))</sup>|
 <a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([110](#notes-110))</sup>|
-<a name='total'></a>**237 operators** | **215** | **209** | **108** | **93** | **76** |
+<a name='total'></a>**237 operators** | **215** | **209** | **111** | **95** | **76** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -372,25 +372,19 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 17. Single.concatMapMaybe()
 18. Maybe.concatMapSingle()
 19. Single.concatMapSingle()
-20. Maybe.dematerialize()
-21. Maybe.doOnLifecycle()
-22. Single.doOnLifecycle()
-23. Completable.doOnLifecycle()
-24. Single.mergeArray()
-25. Single.mergeArrayDelayError()
-26. Single.ofType()
-27. Completable.onErrorReturn()
-28. Completable.onErrorReturnItem()
-29. Maybe.safeSubscribe()
-30. Single.safeSubscribe()
-31. Completable.safeSubscribe()
-32. Completable.sequenceEqual()
-33. Maybe.startWith()
-34. Single.startWith()
-35. Maybe.timeInterval()
-36. Single.timeInterval()
-37. Completable.timeInterval()
-38. Maybe.timestamp()
-39. Single.timestamp()
-40. Maybe.toFuture()
-41. Completable.toFuture()
+20. Maybe.doOnLifecycle()
+21. Single.doOnLifecycle()
+22. Completable.doOnLifecycle()
+23. Single.mergeArray()
+24. Single.mergeArrayDelayError()
+25. Single.ofType()
+26. Completable.onErrorReturn()
+27. Completable.onErrorReturnItem()
+28. Maybe.safeSubscribe()
+29. Single.safeSubscribe()
+30. Completable.safeSubscribe()
+31. Completable.sequenceEqual()
+32. Maybe.startWith()
+33. Single.startWith()
+34. Maybe.toFuture()
+35. Completable.toFuture()
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 12ab3678e2..03e73abe65 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -34,7 +34,7 @@
 import io.reactivex.rxjava3.internal.util.ErrorMode;
 import io.reactivex.rxjava3.observers.TestObserver;
 import io.reactivex.rxjava3.plugins.RxJavaPlugins;
-import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.schedulers.*;
 
 /**
  * The {@code Maybe} class represents a deferred computation and emission of a single value, no value at all or an exception.
@@ -4991,6 +4991,232 @@ public final <U> Maybe<T> takeUntil(@NonNull Publisher<U> other) {
         return RxJavaPlugins.onAssembly(new MaybeTakeUntilPublisher<>(this, other));
     }
 
+    /**
+     * Measures the time (in milliseconds) between the subscription and success item emission
+     * of the current {@code Maybe} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="352" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeInterval.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timeInterval()}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the {@code computation} {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @return the new {@code Maybe} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Maybe<Timed<T>> timeInterval() {
+        return timeInterval(TimeUnit.MILLISECONDS, Schedulers.computation());
+    }
+
+    /**
+     * Measures the time (in milliseconds) between the subscription and success item emission
+     * of the current {@code Maybe} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="355" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeInterval.s.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timeInterval(Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the provided {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Maybe<Timed<T>> timeInterval(@NonNull Scheduler scheduler) {
+        return timeInterval(TimeUnit.MILLISECONDS, scheduler);
+    }
+
+    /**
+     * Measures the time between the subscription and success item emission
+     * of the current {@code Maybe} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="352" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeInterval.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timeInterval(TimeUnit)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the {@code computation} {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code unit} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Maybe<Timed<T>> timeInterval(@NonNull TimeUnit unit) {
+        return timeInterval(unit, Schedulers.computation());
+    }
+
+    /**
+     * Measures the time between the subscription and success item emission
+     * of the current {@code Maybe} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="355" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeInterval.s.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timeInterval(TimeUnit, Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the provided {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Maybe<Timed<T>> timeInterval(@NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        Objects.requireNonNull(unit, "unit is null");
+        Objects.requireNonNull(scheduler, "scheduler is null");
+        return RxJavaPlugins.onAssembly(new MaybeTimeInterval<>(this, unit, scheduler, true));
+    }
+
+    /**
+     * Combines the success value from the current {@code Maybe} with the current time (in milliseconds) of
+     * its reception, using the {@code computation} {@link Scheduler} as time source,
+     * then signals them as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="352" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timestamp.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timestamp()}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the {@code computation} {@code Scheduler}
+     *  for determining the current time upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @return the new {@code Maybe} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Maybe<Timed<T>> timestamp() {
+        return timestamp(TimeUnit.MILLISECONDS, Schedulers.computation());
+    }
+
+    /**
+     * Combines the success value from the current {@code Maybe} with the current time (in milliseconds) of
+     * its reception, using the given {@link Scheduler} as time source,
+     * then signals them as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="355" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timestamp.s.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timestamp(Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the provided {@code Scheduler}
+     *  for determining the current time upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Maybe<Timed<T>> timestamp(@NonNull Scheduler scheduler) {
+        return timestamp(TimeUnit.MILLISECONDS, scheduler);
+    }
+
+    /**
+     * Combines the success value from the current {@code Maybe} with the current time of
+     * its reception, using the {@code computation} {@link Scheduler} as time source,
+     * then signals it as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="352" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timestamp.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timestamp(TimeUnit)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the {@code computation} {@code Scheduler},
+     *  for determining the current time upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code unit} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Maybe<Timed<T>> timestamp(@NonNull TimeUnit unit) {
+        return timestamp(unit, Schedulers.computation());
+    }
+
+    /**
+     * Combines the success value from the current {@code Maybe} with the current time of
+     * its reception, using the given {@link Scheduler} as time source,
+     * then signals it as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="355" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timestamp.s.png" alt="">
+     * <p>
+     * If the current {@code Maybe} is empty or fails, the resulting {@code Maybe} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link Single#timestamp(TimeUnit, Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the provided {@code Scheduler},
+     *  which is used for determining the current time upon receiving the
+     *  success item from the current {@code Maybe}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Maybe<Timed<T>> timestamp(@NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        Objects.requireNonNull(unit, "unit is null");
+        Objects.requireNonNull(scheduler, "scheduler is null");
+        return RxJavaPlugins.onAssembly(new MaybeTimeInterval<>(this, unit, scheduler, false));
+    }
+
     /**
      * Returns a {@code Maybe} that mirrors the current {@code Maybe} but applies a timeout policy for each emitted
      * item. If the next item isn't emitted within the specified timeout duration starting from its predecessor,
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index a3b536b1f7..697c1355b5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -36,7 +36,7 @@
 import io.reactivex.rxjava3.internal.util.ErrorMode;
 import io.reactivex.rxjava3.observers.TestObserver;
 import io.reactivex.rxjava3.plugins.RxJavaPlugins;
-import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.schedulers.*;
 
 /**
  * The {@code Single} class implements the Reactive Pattern for a single value response.
@@ -4137,6 +4137,232 @@ public final Single<T> subscribeOn(@NonNull Scheduler scheduler) {
         return RxJavaPlugins.onAssembly(new SingleSubscribeOn<>(this, scheduler));
     }
 
+    /**
+     * Measures the time (in milliseconds) between the subscription and success item emission
+     * of the current {@code Single} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="466" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeInterval.png" alt="">
+     * <p>
+     * If the current {@code Single} fails, the resulting {@code Single} will
+     * pass along the signal to the downstream. To measure the time to error,
+     * use {@link #materialize()} and apply {@link #timeInterval()}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the {@code computation} {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @return the new {@code Single} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Single<Timed<T>> timeInterval() {
+        return timeInterval(TimeUnit.MILLISECONDS, Schedulers.computation());
+    }
+
+    /**
+     * Measures the time (in milliseconds) between the subscription and success item emission
+     * of the current {@code Single} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="463" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeInterval.s.png" alt="">
+     * <p>
+     * If the current {@code Single} fails, the resulting {@code Single} will
+     * pass along the signal to the downstream. To measure the time to error,
+     * use {@link #materialize()} and apply {@link #timeInterval(Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the provided {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Single<Timed<T>> timeInterval(@NonNull Scheduler scheduler) {
+        return timeInterval(TimeUnit.MILLISECONDS, scheduler);
+    }
+
+    /**
+     * Measures the time between the subscription and success item emission
+     * of the current {@code Single} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="466" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeInterval.png" alt="">
+     * <p>
+     * If the current {@code Single} fails, the resulting {@code Single} will
+     * pass along the signals to the downstream. To measure the time to error,
+     * use {@link #materialize()} and apply {@link #timeInterval(TimeUnit, Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the {@code computation} {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code unit} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Single<Timed<T>> timeInterval(@NonNull TimeUnit unit) {
+        return timeInterval(unit, Schedulers.computation());
+    }
+
+    /**
+     * Measures the time between the subscription and success item emission
+     * of the current {@code Single} and signals it as a tuple ({@link Timed})
+     * success value.
+     * <p>
+     * <img width="640" height="463" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeInterval.s.png" alt="">
+     * <p>
+     * If the current {@code Single} is empty or fails, the resulting {@code Single} will
+     * pass along the signals to the downstream. To measure the time to termination,
+     * use {@link #materialize()} and apply {@link #timeInterval(TimeUnit, Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timeInterval} uses the provided {@link Scheduler}
+     *  for determining the current time upon subscription and upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Single<Timed<T>> timeInterval(@NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        Objects.requireNonNull(unit, "unit is null");
+        Objects.requireNonNull(scheduler, "scheduler is null");
+        return RxJavaPlugins.onAssembly(new SingleTimeInterval<>(this, unit, scheduler, true));
+    }
+
+    /**
+     * Combines the success value from the current {@code Single} with the current time (in milliseconds) of
+     * its reception, using the {@code computation} {@link Scheduler} as time source,
+     * then signals them as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="465" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timestamp.png" alt="">
+     * <p>
+     * If the current {@code Single} is empty or fails, the resulting {@code Single} will
+     * pass along the signals to the downstream. To get the timestamp of the error,
+     * use {@link #materialize()} and apply {@link #timestamp()}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the {@code computation} {@code Scheduler}
+     *  for determining the current time upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @return the new {@code Single} instance
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Single<Timed<T>> timestamp() {
+        return timestamp(TimeUnit.MILLISECONDS, Schedulers.computation());
+    }
+
+    /**
+     * Combines the success value from the current {@code Single} with the current time (in milliseconds) of
+     * its reception, using the given {@link Scheduler} as time source,
+     * then signals them as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="465" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timestamp.s.png" alt="">
+     * <p>
+     * If the current {@code Single} is empty or fails, the resulting {@code Single} will
+     * pass along the signals to the downstream. To get the timestamp of the error,
+     * use {@link #materialize()} and apply {@link #timestamp(Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the provided {@code Scheduler}
+     *  for determining the current time upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Single<Timed<T>> timestamp(@NonNull Scheduler scheduler) {
+        return timestamp(TimeUnit.MILLISECONDS, scheduler);
+    }
+
+    /**
+     * Combines the success value from the current {@code Single} with the current time of
+     * its reception, using the {@code computation} {@link Scheduler} as time source,
+     * then signals it as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="465" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timestamp.png" alt="">
+     * <p>
+     * If the current {@code Single} is empty or fails, the resulting {@code Single} will
+     * pass along the signals to the downstream. To get the timestamp of the error,
+     * use {@link #materialize()} and apply {@link #timestamp(TimeUnit)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the {@code computation} {@code Scheduler},
+     *  for determining the current time upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code unit} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.COMPUTATION)
+    public final Single<Timed<T>> timestamp(@NonNull TimeUnit unit) {
+        return timestamp(unit, Schedulers.computation());
+    }
+
+    /**
+     * Combines the success value from the current {@code Single} with the current time of
+     * its reception, using the given {@link Scheduler} as time source,
+     * then signals it as a {@link Timed} instance.
+     * <p>
+     * <img width="640" height="465" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timestamp.s.png" alt="">
+     * <p>
+     * If the current {@code Single} is empty or fails, the resulting {@code Single} will
+     * pass along the signals to the downstream. To get the timestamp of the error,
+     * use {@link #materialize()} and apply {@link #timestamp(TimeUnit, Scheduler)}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code timestamp} uses the provided {@code Scheduler},
+     *  which is used for determining the current time upon receiving the
+     *  success item from the current {@code Single}.</dd>
+     * </dl>
+     * @param unit the time unit for measurement
+     * @param scheduler the {@code Scheduler} used for providing the current time
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code unit} or {@code scheduler} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.CUSTOM)
+    public final Single<Timed<T>> timestamp(@NonNull TimeUnit unit, @NonNull Scheduler scheduler) {
+        Objects.requireNonNull(unit, "unit is null");
+        Objects.requireNonNull(scheduler, "scheduler is null");
+        return RxJavaPlugins.onAssembly(new SingleTimeInterval<>(this, unit, scheduler, false));
+    }
+
     /**
      * Returns a {@code Single} that emits the item emitted by the current {@code Single} until a {@link CompletableSource} terminates. Upon
      * termination of {@code other}, this will emit a {@link CancellationException} rather than go to
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeInterval.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeInterval.java
new file mode 100644
index 0000000000..af30ee3a1d
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeInterval.java
@@ -0,0 +1,105 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import java.util.concurrent.TimeUnit;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+import io.reactivex.rxjava3.schedulers.Timed;
+
+/**
+ * Measures the time between subscription and the success item emission
+ * from the upstream and emits this as a {@link Timed} success value.
+ * @param <T> the element type of the sequence
+ * @since 3.0.0
+ */
+public final class MaybeTimeInterval<T> extends Maybe<Timed<T>> {
+
+    final MaybeSource<T> source;
+
+    final TimeUnit unit;
+
+    final Scheduler scheduler;
+
+    final boolean start;
+
+    public MaybeTimeInterval(MaybeSource<T> source, TimeUnit unit, Scheduler scheduler, boolean start) {
+        this.source = source;
+        this.unit = unit;
+        this.scheduler = scheduler;
+        this.start = start;
+    }
+
+    @Override
+    protected void subscribeActual(@NonNull MaybeObserver<? super @NonNull Timed<T>> observer) {
+        source.subscribe(new TimeIntervalMaybeObserver<>(observer, unit, scheduler, start));
+    }
+
+    static final class TimeIntervalMaybeObserver<T> implements MaybeObserver<T>, Disposable {
+
+        final MaybeObserver<? super Timed<T>> downstream;
+
+        final TimeUnit unit;
+
+        final Scheduler scheduler;
+
+        final long startTime;
+
+        Disposable upstream;
+
+        TimeIntervalMaybeObserver(MaybeObserver<? super Timed<T>> downstream, TimeUnit unit, Scheduler scheduler, boolean start) {
+            this.downstream = downstream;
+            this.unit = unit;
+            this.scheduler = scheduler;
+            this.startTime = start ? scheduler.now(unit) : 0L;
+        }
+
+        @Override
+        public void onSubscribe(@NonNull Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(@NonNull T t) {
+            downstream.onSuccess(new Timed<>(t, scheduler.now(unit) - startTime, unit));
+        }
+
+        @Override
+        public void onError(@NonNull Throwable e) {
+            downstream.onError(e);
+        }
+
+        @Override
+        public void onComplete() {
+            downstream.onComplete();
+        }
+
+        @Override
+        public void dispose() {
+            upstream.dispose();
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeInterval.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeInterval.java
new file mode 100644
index 0000000000..2eac3bbc3a
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeInterval.java
@@ -0,0 +1,100 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.concurrent.TimeUnit;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+import io.reactivex.rxjava3.schedulers.Timed;
+
+/**
+ * Measures the time between subscription and the success item emission
+ * from the upstream and emits this as a {@link Timed} success value.
+ * @param <T> the element type of the sequence
+ * @since 3.0.0
+ */
+public final class SingleTimeInterval<T> extends Single<Timed<T>> {
+
+    final SingleSource<T> source;
+
+    final TimeUnit unit;
+
+    final Scheduler scheduler;
+
+    final boolean start;
+
+    public SingleTimeInterval(SingleSource<T> source, TimeUnit unit, Scheduler scheduler, boolean start) {
+        this.source = source;
+        this.unit = unit;
+        this.scheduler = scheduler;
+        this.start = start;
+    }
+
+    @Override
+    protected void subscribeActual(@NonNull SingleObserver<? super @NonNull Timed<T>> observer) {
+        source.subscribe(new TimeIntervalSingleObserver<>(observer, unit, scheduler, start));
+    }
+
+    static final class TimeIntervalSingleObserver<T> implements SingleObserver<T>, Disposable {
+
+        final SingleObserver<? super Timed<T>> downstream;
+
+        final TimeUnit unit;
+
+        final Scheduler scheduler;
+
+        final long startTime;
+
+        Disposable upstream;
+
+        TimeIntervalSingleObserver(SingleObserver<? super Timed<T>> downstream, TimeUnit unit, Scheduler scheduler, boolean start) {
+            this.downstream = downstream;
+            this.unit = unit;
+            this.scheduler = scheduler;
+            this.startTime = start ? scheduler.now(unit) : 0L;
+        }
+
+        @Override
+        public void onSubscribe(@NonNull Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(@NonNull T t) {
+            downstream.onSuccess(new Timed<>(t, scheduler.now(unit) - startTime, unit));
+        }
+
+        @Override
+        public void onError(@NonNull Throwable e) {
+            downstream.onError(e);
+        }
+
+        @Override
+        public void dispose() {
+            upstream.dispose();
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/schedulers/Timed.java b/src/main/java/io/reactivex/rxjava3/schedulers/Timed.java
index 814b223dcf..a7b6cc46e7 100644
--- a/src/main/java/io/reactivex/rxjava3/schedulers/Timed.java
+++ b/src/main/java/io/reactivex/rxjava3/schedulers/Timed.java
@@ -33,10 +33,10 @@ public final class Timed<T> {
      * @param value the value to hold
      * @param time the time to hold
      * @param unit the time unit, not null
-     * @throws NullPointerException if unit is {@code null}
+     * @throws NullPointerException if {@code value} or {@code unit} is {@code null}
      */
     public Timed(@NonNull T value, long time, @NonNull TimeUnit unit) {
-        this.value = value;
+        this.value = Objects.requireNonNull(value, "value is null");
         this.time = time;
         this.unit = Objects.requireNonNull(unit, "unit is null");
     }
@@ -89,7 +89,7 @@ public boolean equals(Object other) {
 
     @Override
     public int hashCode() {
-         int h = value != null ? value.hashCode() : 0;
+         int h = value.hashCode();
          h = h * 31 + (int)((time >>> 31) ^ time);
          h = h * 31 + unit.hashCode();
          return h;
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeIntervalTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeIntervalTest.java
new file mode 100644
index 0000000000..30b770aed4
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimeIntervalTest.java
@@ -0,0 +1,111 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Maybe;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.*;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeTimeIntervalTest {
+
+    @Test
+    public void just() {
+        Maybe.just(1)
+        .timeInterval()
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void empty() {
+        Maybe.empty()
+        .timeInterval()
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void error() {
+        Maybe.error(new TestException())
+        .timeInterval()
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justSeconds() {
+        Maybe.just(1)
+        .timeInterval(TimeUnit.SECONDS)
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justScheduler() {
+        Maybe.just(1)
+        .timeInterval(Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justSecondsScheduler() {
+        Maybe.just(1)
+        .timeInterval(TimeUnit.SECONDS, Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeMaybe(m -> m.timeInterval());
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(MaybeSubject.create().timeInterval());
+    }
+
+    @Test
+    public void timeInfo() {
+        TestScheduler scheduler = new TestScheduler();
+
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        TestObserver<Timed<Integer>> to = ms
+        .timeInterval(scheduler)
+        .test();
+
+        scheduler.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+
+        ms.onSuccess(1);
+
+        to.assertResult(new Timed<>(1, 1000L, TimeUnit.MILLISECONDS));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimestampTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimestampTest.java
new file mode 100644
index 0000000000..1ce230f8d0
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeTimestampTest.java
@@ -0,0 +1,111 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Maybe;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.*;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeTimestampTest {
+
+    @Test
+    public void just() {
+        Maybe.just(1)
+        .timestamp()
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void empty() {
+        Maybe.empty()
+        .timestamp()
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void error() {
+        Maybe.error(new TestException())
+        .timestamp()
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justSeconds() {
+        Maybe.just(1)
+        .timestamp(TimeUnit.SECONDS)
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justScheduler() {
+        Maybe.just(1)
+        .timestamp(Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justSecondsScheduler() {
+        Maybe.just(1)
+        .timestamp(TimeUnit.SECONDS, Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeMaybe(m -> m.timestamp());
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(MaybeSubject.create().timestamp());
+    }
+
+    @Test
+    public void timeInfo() {
+        TestScheduler scheduler = new TestScheduler();
+
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        TestObserver<Timed<Integer>> to = ms
+        .timestamp(scheduler)
+        .test();
+
+        scheduler.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+
+        ms.onSuccess(1);
+
+        to.assertResult(new Timed<>(1, 1000L, TimeUnit.MILLISECONDS));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeIntervalTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeIntervalTest.java
new file mode 100644
index 0000000000..09dd26eeba
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimeIntervalTest.java
@@ -0,0 +1,103 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.*;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleTimeIntervalTest {
+
+    @Test
+    public void just() {
+        Single.just(1)
+        .timestamp()
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void error() {
+        Single.error(new TestException())
+        .timestamp()
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justSeconds() {
+        Single.just(1)
+        .timestamp(TimeUnit.SECONDS)
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justScheduler() {
+        Single.just(1)
+        .timestamp(Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justSecondsScheduler() {
+        Single.just(1)
+        .timestamp(TimeUnit.SECONDS, Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingle(m -> m.timestamp());
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(SingleSubject.create().timestamp());
+    }
+
+    @Test
+    public void timeInfo() {
+        TestScheduler scheduler = new TestScheduler();
+
+        SingleSubject<Integer> ss = SingleSubject.create();
+
+        TestObserver<Timed<Integer>> to = ss
+        .timestamp(scheduler)
+        .test();
+
+        scheduler.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+
+        ss.onSuccess(1);
+
+        to.assertResult(new Timed<>(1, 1000L, TimeUnit.MILLISECONDS));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimestampTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimestampTest.java
new file mode 100644
index 0000000000..a282c0345e
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleTimestampTest.java
@@ -0,0 +1,103 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.schedulers.*;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleTimestampTest {
+
+    @Test
+    public void just() {
+        Single.just(1)
+        .timeInterval()
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void error() {
+        Single.error(new TestException())
+        .timeInterval()
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justSeconds() {
+        Single.just(1)
+        .timeInterval(TimeUnit.SECONDS)
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justScheduler() {
+        Single.just(1)
+        .timeInterval(Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void justSecondsScheduler() {
+        Single.just(1)
+        .timeInterval(TimeUnit.SECONDS, Schedulers.single())
+        .test()
+        .assertValueCount(1)
+        .assertNoErrors()
+        .assertComplete();
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingle(m -> m.timeInterval());
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(SingleSubject.create().timeInterval());
+    }
+
+    @Test
+    public void timeInfo() {
+        TestScheduler scheduler = new TestScheduler();
+
+        SingleSubject<Integer> ss = SingleSubject.create();
+
+        TestObserver<Timed<Integer>> to = ss
+        .timeInterval(scheduler)
+        .test();
+
+        scheduler.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+
+        ss.onSuccess(1);
+
+        to.assertResult(new Timed<>(1, 1000L, TimeUnit.MILLISECONDS));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index 60b5a11fb6..a0ba3e52e4 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -458,6 +458,7 @@ static String findNotes(String clazzName, String operatorName) {
             "    C throttleLatest                       Always empty thus no items to work with.",
             "  MS  throttleWithTimeout                  At most one item signaled so no subsequent items to work with.",
             "    C throttleWithTimeout                  Always empty thus no items to work with.",
+            "    C timeInterval                         Always empty thus no items to work with.",
             "    C timestamp                            Always empty thus no items to work with.",
             "FO    toCompletionStage                    Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).",
             "F     toFlowable                           Would be no-op.",
diff --git a/src/test/java/io/reactivex/rxjava3/schedulers/TimedTest.java b/src/test/java/io/reactivex/rxjava3/schedulers/TimedTest.java
index d7a5eb752e..ce117c2fb7 100644
--- a/src/test/java/io/reactivex/rxjava3/schedulers/TimedTest.java
+++ b/src/test/java/io/reactivex/rxjava3/schedulers/TimedTest.java
@@ -39,7 +39,7 @@ public void hashCodeOf() {
 
         assertEquals(TimeUnit.SECONDS.hashCode() + 31 * (5 + 31 * 1), t1.hashCode());
 
-        Timed<Integer> t2 = new Timed<>(null, 5, TimeUnit.SECONDS);
+        Timed<Integer> t2 = new Timed<>(0, 5, TimeUnit.SECONDS);
 
         assertEquals(TimeUnit.SECONDS.hashCode() + 31 * (5 + 31 * 0), t2.hashCode());
     }
diff --git a/src/test/java/io/reactivex/rxjava3/validators/JavadocWording.java b/src/test/java/io/reactivex/rxjava3/validators/JavadocWording.java
index d351e7809d..e22fdd9521 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/JavadocWording.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/JavadocWording.java
@@ -153,12 +153,12 @@ public void maybeDocRefersToMaybeTypes() throws Exception {
                 jdx = 0;
                 for (;;) {
                     int idx = m.javadoc.indexOf("Single", jdx);
-                    if (idx >= 0) {
+                    if (idx >= 0 && m.javadoc.indexOf("Single#", jdx) != idx) {
                         int j = m.javadoc.indexOf("#toSingle", jdx);
                         int k = m.javadoc.indexOf("{@code Single", jdx);
                         if (!m.signature.contains("Single") && (j + 3 != idx && k + 7 != idx)) {
                             e.append("java.lang.RuntimeException: Maybe doc mentions Single but not in the signature\r\n at io.reactivex.rxjava3.core.")
-                            .append("Maybe(Maybe.java:").append(m.javadocLine + lineNumber(m.javadoc, idx) - 1).append(")\r\n\r\n");
+                            .append("Maybe.method(Maybe.java:").append(m.javadocLine + lineNumber(m.javadoc, idx) - 1).append(")\r\n\r\n");
                         }
                         jdx = idx + 6;
                     } else {

From 8c85f5a52115b419beeb84b0e2dc9bb4aa6bcd0f Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sun, 26 Jan 2020 12:36:52 +0100
Subject: [PATCH 21/37] 3.x: Add Maybe/Completable toFuture (#6875)

* 3.x: Add Maybe/Completable toFuture

* Fix copy-paste mistakes
---
 .../reactivex/rxjava3/core/Completable.java   | 22 +++++
 .../io/reactivex/rxjava3/core/Flowable.java   |  2 +-
 .../java/io/reactivex/rxjava3/core/Maybe.java | 23 +++++
 .../io/reactivex/rxjava3/core/Observable.java |  2 +-
 .../io/reactivex/rxjava3/core/Single.java     |  4 +-
 ...Observer.java => FutureMultiObserver.java} | 18 +++-
 .../completable/CompletableToFutureTest.java  | 76 +++++++++++++++++
 .../operators/maybe/MaybeToFutureTest.java    | 84 +++++++++++++++++++
 8 files changed, 224 insertions(+), 7 deletions(-)
 rename src/main/java/io/reactivex/rxjava3/internal/observers/{FutureSingleObserver.java => FutureMultiObserver.java} (89%)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFutureTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToFutureTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index e965855e00..1c6214e1da 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2892,6 +2892,28 @@ public final <T> Flowable<T> toFlowable() {
         }
         return RxJavaPlugins.onAssembly(new CompletableToFlowable<>(this));
     }
+    /**
+     * Returns a {@link Future} representing the termination of the current {@code Completable}
+     * via a {@code null} value.
+     * <p>
+     * <img width="640" height="433" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/Completable.toFuture.png" alt="">
+     * <p>
+     * Cancelling the {@code Future} will cancel the subscription to the current {@code Completable}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code toFuture} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @return the new {@code Future} instance
+     * @see <a href="http://reactivex.io/documentation/operators/to.html">ReactiveX documentation: To</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Future<Void> toFuture() {
+        return subscribeWith(new FutureMultiObserver<>());
+    }
 
     /**
      * Converts this {@code Completable} into a {@link Maybe}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 3d83d477c5..a994e526c5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -6249,7 +6249,7 @@ public final T blockingSingle(@NonNull T defaultItem) {
     /**
      * Returns a {@link Future} representing the only value emitted by this {@code Flowable}.
      * <p>
-     * <img width="640" height="324" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/Flowable.toFuture.png" alt="">
+     * <img width="640" height="311" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/Flowable.toFuture.png" alt="">
      * <p>
      * If the {@code Flowable} emits more than one item, {@link java.util.concurrent.Future} will receive an
      * {@link java.lang.IndexOutOfBoundsException}. If the {@code Flowable} is empty, {@link java.util.concurrent.Future}
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 03e73abe65..8b1b569aeb 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -4166,6 +4166,29 @@ public final Flowable<T> toFlowable() {
         return RxJavaPlugins.onAssembly(new MaybeToFlowable<>(this));
     }
 
+    /**
+     * Returns a {@link Future} representing the single value emitted by the current {@code Maybe}
+     * or {@code null} if the current {@code Maybe} is empty.
+     * <p>
+     * <img width="640" height="292" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/Maybe.toFuture.png" alt="">
+     * <p>
+     * Cancelling the {@code Future} will cancel the subscription to the current {@code Maybe}.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code toFuture} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @return the new {@code Future} instance
+     * @see <a href="http://reactivex.io/documentation/operators/to.html">ReactiveX documentation: To</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Future<T> toFuture() {
+        return subscribeWith(new FutureMultiObserver<>());
+    }
+
     /**
      * Converts this {@code Maybe} into an {@link Observable} instance composing disposal
      * through.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index 89de9dd63e..3ab0be1ab9 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -5654,7 +5654,7 @@ public final T blockingSingle(@NonNull T defaultItem) {
     /**
      * Returns a {@link Future} representing the only value emitted by the current {@code Observable}.
      * <p>
-     * <img width="640" height="312" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/toFuture.o.png" alt="">
+     * <img width="640" height="299" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/toFuture.o.png" alt="">
      * <p>
      * If the {@code Observable} emits more than one item, {@code Future} will receive an
      * {@link IndexOutOfBoundsException}. If the {@code Observable} is empty, {@code Future}
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 697c1355b5..a283d9eef0 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -4625,6 +4625,8 @@ public final Flowable<T> toFlowable() {
      * Returns a {@link Future} representing the single value emitted by this {@code Single}.
      * <p>
      * <img width="640" height="467" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/Single.toFuture.png" alt="">
+     * <p>
+     * Cancelling the {@code Future} will cancel the subscription to the current {@code Single}.
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code toFuture} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4637,7 +4639,7 @@ public final Flowable<T> toFlowable() {
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public final Future<T> toFuture() {
-        return subscribeWith(new FutureSingleObserver<>());
+        return subscribeWith(new FutureMultiObserver<>());
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/FutureSingleObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/FutureMultiObserver.java
similarity index 89%
rename from src/main/java/io/reactivex/rxjava3/internal/observers/FutureSingleObserver.java
rename to src/main/java/io/reactivex/rxjava3/internal/observers/FutureMultiObserver.java
index 3e55963bea..e2f2aeea5a 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/observers/FutureSingleObserver.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/observers/FutureMultiObserver.java
@@ -19,7 +19,7 @@
 import java.util.concurrent.atomic.AtomicReference;
 
 import io.reactivex.rxjava3.annotations.NonNull;
-import io.reactivex.rxjava3.core.SingleObserver;
+import io.reactivex.rxjava3.core.*;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
 import io.reactivex.rxjava3.internal.util.BlockingHelper;
@@ -31,15 +31,15 @@
  *
  * @param <T> the value type
  */
-public final class FutureSingleObserver<T> extends CountDownLatch
-implements SingleObserver<T>, Future<T>, Disposable {
+public final class FutureMultiObserver<T> extends CountDownLatch
+implements MaybeObserver<T>, SingleObserver<T>, CompletableObserver, Future<T>, Disposable {
 
     T value;
     Throwable error;
 
     final AtomicReference<Disposable> upstream;
 
-    public FutureSingleObserver() {
+    public FutureMultiObserver() {
         super(1);
         this.upstream = new AtomicReference<>();
     }
@@ -141,6 +141,16 @@ public void onError(Throwable t) {
         }
     }
 
+    @Override
+    public void onComplete() {
+        Disposable a = upstream.get();
+        if (a == DisposableHelper.DISPOSED) {
+            return;
+        }
+        upstream.compareAndSet(a, this);
+        countDown();
+    }
+
     @Override
     public void dispose() {
         // ignoring as `this` means a finished Disposable only
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFutureTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFutureTest.java
new file mode 100644
index 0000000000..7501a2fe85
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableToFutureTest.java
@@ -0,0 +1,76 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.junit.Assert.*;
+
+import java.util.concurrent.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.subjects.CompletableSubject;
+
+public class CompletableToFutureTest extends RxJavaTest {
+
+    @Test
+    public void empty() throws Exception {
+        assertNull(Completable.complete()
+        .subscribeOn(Schedulers.computation())
+        .toFuture()
+        .get());
+    }
+
+    @Test
+    public void error() throws InterruptedException {
+        try {
+            Completable.error(new TestException())
+            .subscribeOn(Schedulers.computation())
+            .toFuture()
+            .get();
+
+            fail("Should have thrown!");
+        } catch (ExecutionException ex) {
+            assertTrue("" + ex.getCause(), ex.getCause() instanceof TestException);
+        }
+    }
+
+    @Test
+    public void cancel() {
+        CompletableSubject cs = CompletableSubject.create();
+
+        Future<Void> f = cs.toFuture();
+
+        assertTrue(cs.hasObservers());
+
+        f.cancel(true);
+
+        assertFalse(cs.hasObservers());
+    }
+
+    @Test
+    public void cancel2() {
+        CompletableSubject cs = CompletableSubject.create();
+
+        Future<Void> f = cs.toFuture();
+
+        assertTrue(cs.hasObservers());
+
+        f.cancel(false);
+
+        assertFalse(cs.hasObservers());
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToFutureTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToFutureTest.java
new file mode 100644
index 0000000000..37723dc656
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeToFutureTest.java
@@ -0,0 +1,84 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.junit.Assert.*;
+
+import java.util.concurrent.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+
+public class MaybeToFutureTest extends RxJavaTest {
+
+    @Test
+    public void success() throws Exception {
+        assertEquals((Integer)1, Maybe.just(1)
+        .subscribeOn(Schedulers.computation())
+        .toFuture()
+        .get());
+    }
+
+    @Test
+    public void empty() throws Exception {
+        assertNull(Maybe.empty()
+        .subscribeOn(Schedulers.computation())
+        .toFuture()
+        .get());
+    }
+
+    @Test
+    public void error() throws InterruptedException {
+        try {
+            Maybe.error(new TestException())
+            .subscribeOn(Schedulers.computation())
+            .toFuture()
+            .get();
+
+            fail("Should have thrown!");
+        } catch (ExecutionException ex) {
+            assertTrue("" + ex.getCause(), ex.getCause() instanceof TestException);
+        }
+    }
+
+    @Test
+    public void cancel() {
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        Future<Integer> f = ms.toFuture();
+
+        assertTrue(ms.hasObservers());
+
+        f.cancel(true);
+
+        assertFalse(ms.hasObservers());
+    }
+
+    @Test
+    public void cancel2() {
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        Future<Integer> f = ms.toFuture();
+
+        assertTrue(ms.hasObservers());
+
+        f.cancel(false);
+
+        assertFalse(ms.hasObservers());
+    }
+}

From db0bd715bb512976fb0cac20a89af8176b1e1b22 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sun, 26 Jan 2020 15:44:47 +0100
Subject: [PATCH 22/37] 3.x: Add Single.ofType (#6876)

---
 .../java/io/reactivex/rxjava3/core/Maybe.java |  6 +-
 .../io/reactivex/rxjava3/core/Single.java     | 24 +++++
 .../operators/single/SingleOfTypeTest.java    | 96 +++++++++++++++++++
 .../rxjava3/testsupport/TestHelper.java       | 24 +++++
 4 files changed, 147 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOfTypeTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 8b1b569aeb..b2a6465eae 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -3472,7 +3472,7 @@ public final Maybe<T> doOnSuccess(@NonNull Consumer<? super T> onSuccess) {
      * Filters the success item of the {@code Maybe} via a predicate function and emitting it if the predicate
      * returns {@code true}, completing otherwise.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/filter.png" alt="">
+     * <img width="640" height="291" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.filter.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code filter} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4098,10 +4098,10 @@ public final Maybe<T> observeOn(@NonNull Scheduler scheduler) {
     }
 
     /**
-     * Filters the items emitted by a {@code Maybe}, only emitting its success value if that
+     * Filters the items emitted by the current {@code Maybe}, only emitting its success value if that
      * is an instance of the supplied {@link Class}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/ofClass.png" alt="">
+     * <img width="640" height="291" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.ofType.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code ofType} does not operate by default on a particular {@link Scheduler}.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index a283d9eef0..12400b1fd0 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -3439,6 +3439,30 @@ public final Single<Boolean> contains(@NonNull Object item, @NonNull BiPredicate
     public final Flowable<T> mergeWith(@NonNull SingleSource<? extends T> other) {
         return merge(this, other);
     }
+    /**
+     * Filters the items emitted by the current {@code Single}, only emitting its success value if that
+     * is an instance of the supplied {@link Class}.
+     * <p>
+     * <img width="640" height="399" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.ofType.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code ofType} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <U> the output type
+     * @param clazz
+     *            the class type to filter the items emitted by the current {@code Single}
+     * @return the new {@link Maybe} instance
+     * @throws NullPointerException if {@code clazz} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <U> Maybe<U> ofType(@NonNull Class<U> clazz) {
+        Objects.requireNonNull(clazz, "clazz is null");
+        return filter(Functions.isInstanceOf(clazz)).cast(clazz);
+    }
 
     /**
      * Signals the success item or the terminal signals of the current {@code Single} on the specified {@link Scheduler},
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOfTypeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOfTypeTest.java
new file mode 100644
index 0000000000..3ce3a0d15e
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleOfTypeTest.java
@@ -0,0 +1,96 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.processors.PublishProcessor;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleOfTypeTest extends RxJavaTest {
+
+    @Test
+    public void normal() {
+        Single.just(1).ofType(Integer.class)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void normalDowncast() {
+        TestObserver<Number> to = Single.just(1)
+        .ofType(Number.class)
+        .test();
+        // don't make this fluent, target type required!
+        to.assertResult((Number)1);
+    }
+
+    @Test
+    public void notInstance() {
+        TestObserver<String> to = Single.just(1)
+        .ofType(String.class)
+        .test();
+        // don't make this fluent, target type required!
+        to.assertResult();
+    }
+
+    @Test
+    public void error() {
+        TestObserver<Number> to = Single.<Integer>error(new TestException())
+        .ofType(Number.class)
+        .test();
+        // don't make this fluent, target type required!
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void errorNotInstance() {
+        TestObserver<String> to = Single.<Integer>error(new TestException())
+        .ofType(String.class)
+        .test();
+        // don't make this fluent, target type required!
+        to.assertFailure(TestException.class);
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposedSingleToMaybe(new Function<Single<Object>, Maybe<Object>>() {
+            @Override
+            public Maybe<Object> apply(Single<Object> m) throws Exception {
+                return m.ofType(Object.class);
+            }
+        });
+    }
+
+    @Test
+    public void isDisposed() {
+        PublishProcessor<Integer> pp = PublishProcessor.create();
+
+        TestHelper.checkDisposed(pp.singleElement().ofType(Object.class));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingleToMaybe(new Function<Single<Object>, Maybe<Object>>() {
+            @Override
+            public Maybe<Object> apply(Single<Object> f) throws Exception {
+                return f.ofType(Object.class);
+            }
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/testsupport/TestHelper.java b/src/test/java/io/reactivex/rxjava3/testsupport/TestHelper.java
index f50354b6a5..bb6608e96d 100644
--- a/src/test/java/io/reactivex/rxjava3/testsupport/TestHelper.java
+++ b/src/test/java/io/reactivex/rxjava3/testsupport/TestHelper.java
@@ -2248,6 +2248,30 @@ public static <T, U> void checkDisposedMaybeToSingle(Function<Maybe<T>, ? extend
         assertFalse(pp.hasSubscribers());
     }
 
+    /**
+     * Check if the operator applied to a Maybe source propagates dispose properly.
+     * @param <T> the source value type
+     * @param <U> the output value type
+     * @param composer the function to apply an operator to the provided Maybe source
+     */
+    public static <T, U> void checkDisposedSingleToMaybe(Function<Single<T>, ? extends MaybeSource<U>> composer) {
+        PublishProcessor<T> pp = PublishProcessor.create();
+
+        TestSubscriber<U> ts = new TestSubscriber<>();
+
+        try {
+            new MaybeToFlowable<>(composer.apply(pp.singleOrError())).subscribe(ts);
+        } catch (Throwable ex) {
+            throw ExceptionHelper.wrapOrThrow(ex);
+        }
+
+        assertTrue(pp.hasSubscribers());
+
+        ts.cancel();
+
+        assertFalse(pp.hasSubscribers());
+    }
+
     /**
      * Check if the TestSubscriber has a CompositeException with the specified class
      * of Throwables in the given order.

From 4257ef563a3bf017e0703c00057daf12b54738ba Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sun, 26 Jan 2020 17:50:26 +0100
Subject: [PATCH 23/37] 3.x: Add doOnLifecycle to M/S/C (#6877)

---
 docs/Operator-Matrix.md                       |  34 ++--
 .../reactivex/rxjava3/core/Completable.java   |  29 +++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  28 +++
 .../io/reactivex/rxjava3/core/Single.java     |  29 +++
 .../operators/maybe/MaybeDoOnLifecycle.java   | 125 +++++++++++++
 .../operators/single/SingleDoOnLifecycle.java | 119 +++++++++++++
 .../CompletableDoOnLifecycleTest.java         | 153 ++++++++++++++++
 .../maybe/MaybeDoOnLifecycleTest.java         | 168 ++++++++++++++++++
 .../single/SingleDoOnLifecycleTest.java       | 152 ++++++++++++++++
 9 files changed, 817 insertions(+), 20 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycle.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycle.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableDoOnLifecycleTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycleTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycleTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 10427533cc..a44eed94ec 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -71,7 +71,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='doOnError'></a>`doOnError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([46](#notes-46))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
 <a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
 <a name='doOnSubscribe'></a>`doOnSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -144,7 +144,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='mergeWith'></a>`mergeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='never'></a>`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='observeOn'></a>`observeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([82](#notes-82))</sup>|
+<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([82](#notes-82))</sup>|
 <a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
 <a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
 <a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
@@ -219,7 +219,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toList'></a>`toList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='toMap'></a>`toMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -237,7 +237,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([108](#notes-108))</sup>|
 <a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([109](#notes-109))</sup>|
 <a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([110](#notes-110))</sup>|
-<a name='total'></a>**237 operators** | **215** | **209** | **111** | **95** | **76** |
+<a name='total'></a>**237 operators** | **215** | **209** | **113** | **97** | **78** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -372,19 +372,13 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 17. Single.concatMapMaybe()
 18. Maybe.concatMapSingle()
 19. Single.concatMapSingle()
-20. Maybe.doOnLifecycle()
-21. Single.doOnLifecycle()
-22. Completable.doOnLifecycle()
-23. Single.mergeArray()
-24. Single.mergeArrayDelayError()
-25. Single.ofType()
-26. Completable.onErrorReturn()
-27. Completable.onErrorReturnItem()
-28. Maybe.safeSubscribe()
-29. Single.safeSubscribe()
-30. Completable.safeSubscribe()
-31. Completable.sequenceEqual()
-32. Maybe.startWith()
-33. Single.startWith()
-34. Maybe.toFuture()
-35. Completable.toFuture()
+20. Single.mergeArray()
+21. Single.mergeArrayDelayError()
+22. Completable.onErrorReturn()
+23. Completable.onErrorReturnItem()
+24. Maybe.safeSubscribe()
+25. Single.safeSubscribe()
+26. Completable.safeSubscribe()
+27. Completable.sequenceEqual()
+28. Maybe.startWith()
+29. Single.startWith()
diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 1c6214e1da..9febbd1204 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -18,6 +18,7 @@
 import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
+import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.exceptions.*;
 import io.reactivex.rxjava3.functions.*;
@@ -1751,6 +1752,34 @@ public final Completable doOnEvent(@NonNull Consumer<@Nullable ? super Throwable
         return RxJavaPlugins.onAssembly(new CompletableDoOnEvent(this, onEvent));
     }
 
+    /**
+     * Calls the appropriate {@code onXXX} method (shared between all {@link CompletableObserver}s) for the lifecycle events of
+     * the sequence (subscription, disposal).
+     * <p>
+     * <img width="640" height="257" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.doOnLifecycle.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code doOnLifecycle} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param onSubscribe
+     *              a {@link Consumer} called with the {@link Disposable} sent via {@link CompletableObserver#onSubscribe(Disposable)}
+     * @param onDispose
+     *              called when the downstream disposes the {@code Disposable} via {@code dispose()}
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code onSubscribe} or {@code onDispose} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Completable doOnLifecycle(@NonNull Consumer<? super Disposable> onSubscribe, @NonNull Action onDispose) {
+        return doOnLifecycle(onSubscribe, Functions.emptyConsumer(),
+                Functions.EMPTY_ACTION, Functions.EMPTY_ACTION,
+                Functions.EMPTY_ACTION, onDispose);
+    }
+
     /**
      * Returns a {@code Completable} instance that calls the various callbacks upon the specific
      * lifecycle events.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index b2a6465eae..b3ed8213d4 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -3388,6 +3388,34 @@ public final Maybe<T> doOnEvent(@NonNull BiConsumer<@Nullable ? super T, @Nullab
         return RxJavaPlugins.onAssembly(new MaybeDoOnEvent<>(this, onEvent));
     }
 
+    /**
+     * Calls the appropriate {@code onXXX} method (shared between all {@link MaybeObserver}s) for the lifecycle events of
+     * the sequence (subscription, disposal).
+     * <p>
+     * <img width="640" height="183" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doOnLifecycle.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code doOnLifecycle} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param onSubscribe
+     *              a {@link Consumer} called with the {@link Disposable} sent via {@link MaybeObserver#onSubscribe(Disposable)}
+     * @param onDispose
+     *              called when the downstream disposes the {@code Disposable} via {@code dispose()}
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code onSubscribe} or {@code onDispose} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Maybe<T> doOnLifecycle(@NonNull Consumer<? super Disposable> onSubscribe, @NonNull Action onDispose) {
+        Objects.requireNonNull(onSubscribe, "onSubscribe is null");
+        Objects.requireNonNull(onDispose, "onDispose is null");
+        return RxJavaPlugins.onAssembly(new MaybeDoOnLifecycle<>(this, onSubscribe, onDispose));
+    }
+
     /**
      * Calls the shared {@link Consumer} with the {@link Disposable} sent through the {@code onSubscribe} for each
      * {@link MaybeObserver} that subscribes to the current {@code Maybe}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 12400b1fd0..81b0aaaffe 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -2684,6 +2684,34 @@ public final Single<T> doFinally(@NonNull Action onFinally) {
         return RxJavaPlugins.onAssembly(new SingleDoFinally<>(this, onFinally));
     }
 
+    /**
+     * Calls the appropriate {@code onXXX} method (shared between all {@link SingleObserver}s) for the lifecycle events of
+     * the sequence (subscription, disposal).
+     * <p>
+     * <img width="640" height="232" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.doOnLifecycle.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code doOnLifecycle} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param onSubscribe
+     *              a {@link Consumer} called with the {@link Disposable} sent via {@link SingleObserver#onSubscribe(Disposable)}
+     * @param onDispose
+     *              called when the downstream disposes the {@code Disposable} via {@code dispose()}
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code onSubscribe} or {@code onDispose} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public final Single<T> doOnLifecycle(@NonNull Consumer<? super Disposable> onSubscribe, @NonNull Action onDispose) {
+        Objects.requireNonNull(onSubscribe, "onSubscribe is null");
+        Objects.requireNonNull(onDispose, "onDispose is null");
+        return RxJavaPlugins.onAssembly(new SingleDoOnLifecycle<>(this, onSubscribe, onDispose));
+    }
+
     /**
      * Calls the shared consumer with the {@link Disposable} sent through the {@code onSubscribe} for each
      * {@link SingleObserver} that subscribes to the current {@code Single}.
@@ -3455,6 +3483,7 @@ public final Flowable<T> mergeWith(@NonNull SingleSource<? extends T> other) {
      * @return the new {@link Maybe} instance
      * @throws NullPointerException if {@code clazz} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
+     * @since 3.0.0
      */
     @CheckReturnValue
     @NonNull
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycle.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycle.java
new file mode 100644
index 0000000000..3355c79014
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycle.java
@@ -0,0 +1,125 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.disposables.*;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Invokes callbacks upon {@code onSubscribe} from upstream and
+ * {@code dispose} from downstream.
+ *
+ * @param <T> the element type of the flow
+ * @since 3.0.0
+ */
+public final class MaybeDoOnLifecycle<T> extends AbstractMaybeWithUpstream<T, T> {
+
+    final Consumer<? super Disposable> onSubscribe;
+
+    final Action onDispose;
+
+    public MaybeDoOnLifecycle(Maybe<T> upstream, Consumer<? super Disposable> onSubscribe,
+            Action onDispose) {
+        super(upstream);
+        this.onSubscribe = onSubscribe;
+        this.onDispose = onDispose;
+    }
+
+    @Override
+    protected void subscribeActual(MaybeObserver<? super T> observer) {
+        source.subscribe(new MaybeLifecycleObserver<>(observer, onSubscribe, onDispose));
+    }
+
+    static final class MaybeLifecycleObserver<T> implements MaybeObserver<T>, Disposable {
+
+        final MaybeObserver<? super T> downstream;
+
+        final Consumer<? super Disposable> onSubscribe;
+
+        final Action onDispose;
+
+        Disposable upstream;
+
+        MaybeLifecycleObserver(MaybeObserver<? super T> downstream, Consumer<? super Disposable> onSubscribe, Action onDispose) {
+            this.downstream = downstream;
+            this.onSubscribe = onSubscribe;
+            this.onDispose = onDispose;
+        }
+
+        @Override
+        public void onSubscribe(@NonNull Disposable d) {
+            // this way, multiple calls to onSubscribe can show up in tests that use doOnSubscribe to validate behavior
+            try {
+                onSubscribe.accept(d);
+            } catch (Throwable e) {
+                Exceptions.throwIfFatal(e);
+                d.dispose();
+                this.upstream = DisposableHelper.DISPOSED;
+                EmptyDisposable.error(e, downstream);
+                return;
+            }
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(@NonNull T t) {
+            if (upstream != DisposableHelper.DISPOSED) {
+                upstream = DisposableHelper.DISPOSED;
+                downstream.onSuccess(t);
+            }
+        }
+
+        @Override
+        public void onError(@NonNull Throwable e) {
+            if (upstream != DisposableHelper.DISPOSED) {
+                upstream = DisposableHelper.DISPOSED;
+                downstream.onError(e);
+            } else {
+                RxJavaPlugins.onError(e);
+            }
+        }
+
+        @Override
+        public void onComplete() {
+            if (upstream != DisposableHelper.DISPOSED) {
+                upstream = DisposableHelper.DISPOSED;
+                downstream.onComplete();
+            }
+        }
+
+        @Override
+        public void dispose() {
+            try {
+                onDispose.run();
+            } catch (Throwable e) {
+                Exceptions.throwIfFatal(e);
+                RxJavaPlugins.onError(e);
+            }
+            upstream.dispose();
+            upstream = DisposableHelper.DISPOSED;
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycle.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycle.java
new file mode 100644
index 0000000000..288e8970cd
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycle.java
@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+package io.reactivex.rxjava3.internal.operators.single;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.disposables.*;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Invokes callbacks upon {@code onSubscribe} from upstream and
+ * {@code dispose} from downstream.
+ *
+ * @param <T> the element type of the flow
+ * @since 3.0.0
+ */
+public final class SingleDoOnLifecycle<T> extends Single<T> {
+
+    final Single<T> source;
+
+    final Consumer<? super Disposable> onSubscribe;
+
+    final Action onDispose;
+
+    public SingleDoOnLifecycle(Single<T> upstream, Consumer<? super Disposable> onSubscribe,
+            Action onDispose) {
+        this.source = upstream;
+        this.onSubscribe = onSubscribe;
+        this.onDispose = onDispose;
+    }
+
+    @Override
+    protected void subscribeActual(SingleObserver<? super T> observer) {
+        source.subscribe(new SingleLifecycleObserver<>(observer, onSubscribe, onDispose));
+    }
+
+    static final class SingleLifecycleObserver<T> implements SingleObserver<T>, Disposable {
+
+        final SingleObserver<? super T> downstream;
+
+        final Consumer<? super Disposable> onSubscribe;
+
+        final Action onDispose;
+
+        Disposable upstream;
+
+        SingleLifecycleObserver(SingleObserver<? super T> downstream, Consumer<? super Disposable> onSubscribe, Action onDispose) {
+            this.downstream = downstream;
+            this.onSubscribe = onSubscribe;
+            this.onDispose = onDispose;
+        }
+
+        @Override
+        public void onSubscribe(@NonNull Disposable d) {
+            // this way, multiple calls to onSubscribe can show up in tests that use doOnSubscribe to validate behavior
+            try {
+                onSubscribe.accept(d);
+            } catch (Throwable e) {
+                Exceptions.throwIfFatal(e);
+                d.dispose();
+                this.upstream = DisposableHelper.DISPOSED;
+                EmptyDisposable.error(e, downstream);
+                return;
+            }
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(@NonNull T t) {
+            if (upstream != DisposableHelper.DISPOSED) {
+                upstream = DisposableHelper.DISPOSED;
+                downstream.onSuccess(t);
+            }
+        }
+
+        @Override
+        public void onError(@NonNull Throwable e) {
+            if (upstream != DisposableHelper.DISPOSED) {
+                upstream = DisposableHelper.DISPOSED;
+                downstream.onError(e);
+            } else {
+                RxJavaPlugins.onError(e);
+            }
+        }
+
+        @Override
+        public void dispose() {
+            try {
+                onDispose.run();
+            } catch (Throwable e) {
+                Exceptions.throwIfFatal(e);
+                RxJavaPlugins.onError(e);
+            }
+            upstream.dispose();
+            upstream = DisposableHelper.DISPOSED;
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableDoOnLifecycleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableDoOnLifecycleTest.java
new file mode 100644
index 0000000000..3e85e1e027
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableDoOnLifecycleTest.java
@@ -0,0 +1,153 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.junit.Assert.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.CompletableSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class CompletableDoOnLifecycleTest extends RxJavaTest {
+
+    @Test
+    public void empty() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Completable.complete()
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertResult();
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void error() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Completable.error(new TestException())
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void onSubscribeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+            Action onDispose = mock(Action.class);
+
+            doThrow(new TestException("First")).when(onSubscribe).accept(any());
+
+            Disposable bs = Disposable.empty();
+
+            new Completable() {
+                @Override
+                protected void subscribeActual(CompletableObserver observer) {
+                    observer.onSubscribe(bs);
+                    observer.onError(new TestException("Second"));
+                    observer.onComplete();
+                }
+            }
+            .doOnLifecycle(onSubscribe, onDispose)
+            .to(TestHelper.<Integer>testConsumer())
+            .assertFailureAndMessage(TestException.class, "First");
+
+            assertTrue(bs.isDisposed());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class, "Second");
+
+            verify(onSubscribe).accept(any());
+            verify(onDispose, never()).run();
+        });
+    }
+
+    @Test
+    public void onDisposeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+            Action onDispose = mock(Action.class);
+
+            doThrow(new TestException("First")).when(onDispose).run();
+
+            CompletableSubject cs = CompletableSubject.create();
+
+            TestObserver<Void> to = cs
+            .doOnLifecycle(onSubscribe, onDispose)
+            .test();
+
+            assertTrue(cs.hasObservers());
+
+            to.dispose();
+
+            assertFalse(cs.hasObservers());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class, "First");
+
+            verify(onSubscribe).accept(any());
+            verify(onDispose).run();
+        });
+    }
+
+    @Test
+    public void dispose() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        CompletableSubject cs = CompletableSubject.create();
+
+        TestObserver<Void> to = cs
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test();
+
+        assertTrue(cs.hasObservers());
+
+        to.dispose();
+
+        assertFalse(cs.hasObservers());
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose).run();
+    }
+
+    @Test
+    public void isDisposed() {
+        TestHelper.checkDisposed(CompletableSubject.create().doOnLifecycle(d -> { }, () -> { }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeCompletable(m -> m.doOnLifecycle(d -> { }, () -> { }));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycleTest.java
new file mode 100644
index 0000000000..b8921b7eb9
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeDoOnLifecycleTest.java
@@ -0,0 +1,168 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.MaybeSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeDoOnLifecycleTest extends RxJavaTest {
+
+    @Test
+    public void success() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Maybe.just(1)
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertResult(1);
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void empty() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Maybe.empty()
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertResult();
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void error() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Maybe.error(new TestException())
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void onSubscribeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+            Action onDispose = mock(Action.class);
+
+            doThrow(new TestException("First")).when(onSubscribe).accept(any());
+
+            Disposable bs = Disposable.empty();
+
+            new Maybe<Integer>() {
+                @Override
+                protected void subscribeActual(MaybeObserver<? super Integer> observer) {
+                    observer.onSubscribe(bs);
+                    observer.onError(new TestException("Second"));
+                    observer.onComplete();
+                    observer.onSuccess(1);
+                }
+            }
+            .doOnLifecycle(onSubscribe, onDispose)
+            .to(TestHelper.<Integer>testConsumer())
+            .assertFailureAndMessage(TestException.class, "First");
+
+            assertTrue(bs.isDisposed());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class, "Second");
+
+            verify(onSubscribe).accept(any());
+            verify(onDispose, never()).run();
+        });
+    }
+
+    @Test
+    public void onDisposeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+            Action onDispose = mock(Action.class);
+
+            doThrow(new TestException("First")).when(onDispose).run();
+
+            MaybeSubject<Integer> ms = MaybeSubject.create();
+
+            TestObserver<Integer> to = ms
+            .doOnLifecycle(onSubscribe, onDispose)
+            .test();
+
+            assertTrue(ms.hasObservers());
+
+            to.dispose();
+
+            assertFalse(ms.hasObservers());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class, "First");
+
+            verify(onSubscribe).accept(any());
+            verify(onDispose).run();
+        });
+    }
+
+    @Test
+    public void dispose() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        MaybeSubject<Integer> ms = MaybeSubject.create();
+
+        TestObserver<Integer> to = ms
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test();
+
+        assertTrue(ms.hasObservers());
+
+        to.dispose();
+
+        assertFalse(ms.hasObservers());
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose).run();
+    }
+
+    @Test
+    public void isDisposed() {
+        TestHelper.checkDisposed(MaybeSubject.create().doOnLifecycle(d -> { }, () -> { }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeMaybe(m -> m.doOnLifecycle(d -> { }, () -> { }));
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycleTest.java
new file mode 100644
index 0000000000..9208ab2be8
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleDoOnLifecycleTest.java
@@ -0,0 +1,152 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleDoOnLifecycleTest extends RxJavaTest {
+
+    @Test
+    public void success() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Single.just(1)
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertResult(1);
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void error() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        Single.error(new TestException())
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose, never()).run();
+    }
+
+    @Test
+    public void onSubscribeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+            Action onDispose = mock(Action.class);
+
+            doThrow(new TestException("First")).when(onSubscribe).accept(any());
+
+            Disposable bs = Disposable.empty();
+
+            new Single<Integer>() {
+                @Override
+                protected void subscribeActual(SingleObserver<? super Integer> observer) {
+                    observer.onSubscribe(bs);
+                    observer.onError(new TestException("Second"));
+                    observer.onSuccess(1);
+                }
+            }
+            .doOnLifecycle(onSubscribe, onDispose)
+            .to(TestHelper.<Integer>testConsumer())
+            .assertFailureAndMessage(TestException.class, "First");
+
+            assertTrue(bs.isDisposed());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class, "Second");
+
+            verify(onSubscribe).accept(any());
+            verify(onDispose, never()).run();
+        });
+    }
+
+    @Test
+    public void onDisposeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+            Action onDispose = mock(Action.class);
+
+            doThrow(new TestException("First")).when(onDispose).run();
+
+            SingleSubject<Integer> ss = SingleSubject.create();
+
+            TestObserver<Integer> to = ss
+            .doOnLifecycle(onSubscribe, onDispose)
+            .test();
+
+            assertTrue(ss.hasObservers());
+
+            to.dispose();
+
+            assertFalse(ss.hasObservers());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class, "First");
+
+            verify(onSubscribe).accept(any());
+            verify(onDispose).run();
+        });
+    }
+
+    @Test
+    public void dispose() throws Throwable {
+        @SuppressWarnings("unchecked")
+        Consumer<? super Disposable> onSubscribe = mock(Consumer.class);
+        Action onDispose = mock(Action.class);
+
+        SingleSubject<Integer> ss = SingleSubject.create();
+
+        TestObserver<Integer> to = ss
+        .doOnLifecycle(onSubscribe, onDispose)
+        .test();
+
+        assertTrue(ss.hasObservers());
+
+        to.dispose();
+
+        assertFalse(ss.hasObservers());
+
+        verify(onSubscribe).accept(any());
+        verify(onDispose).run();
+    }
+
+    @Test
+    public void isDisposed() {
+        TestHelper.checkDisposed(SingleSubject.create().doOnLifecycle(d -> { }, () -> { }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingle(m -> m.doOnLifecycle(d -> { }, () -> { }));
+    }
+}

From 57bd1a9272464a1b4b201faa2bab7a929a0ae7f3 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Sun, 26 Jan 2020 20:13:17 +0100
Subject: [PATCH 24/37] 3.x: Add concatMapX operators (aliases) (#6879)

---
 docs/Operator-Matrix.md                       | 458 +++++++++---------
 .../java/io/reactivex/rxjava3/core/Maybe.java |  70 ++-
 .../io/reactivex/rxjava3/core/Single.java     |  80 +++
 .../maybe/MaybeConcatMapCompletableTest.java  |  60 +++
 .../maybe/MaybeConcatMapSingleTest.java       | 142 ++++++
 .../operators/maybe/MaybeConcatMapTest.java   | 101 ++++
 .../SingleConcatMapCompletableTest.java       | 114 +++++
 .../single/SingleConcatMapMaybeTest.java      | 141 ++++++
 .../operators/single/SingleConcatMapTest.java | 132 +++++
 .../util/OperatorMatrixGenerator.java         |   6 +
 10 files changed, 1063 insertions(+), 241 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapCompletableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapSingleTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapCompletableTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapMaybeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index a44eed94ec..cd71558ddb 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -37,102 +37,102 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
 <a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='concatEager'></a>`concatEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use merge().'>([26](#notes-26))</sup>|
-<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='concatMapCompletableDelayError'></a>`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='concatMapDelayError'></a>`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
-<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
-<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatMap.'>([32](#notes-32))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatMap().'>([34](#notes-34))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='concatWith'></a>`concatWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='contains'></a>`contains`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([34](#notes-34))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([35](#notes-35))</sup>|
+<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([38](#notes-38))</sup>|
 <a name='create'></a>`create`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
+<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
 <a name='defer'></a>`defer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delay'></a>`delay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delaySubscription'></a>`delaySubscription`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([41](#notes-41))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([41](#notes-41))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([44](#notes-44))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
 <a name='doAfterTerminate'></a>`doAfterTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doFinally'></a>`doFinally`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([42](#notes-42))</sup>|
-<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([43](#notes-43))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([44](#notes-44))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|
+<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([46](#notes-46))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([47](#notes-47))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
 <a name='doOnError'></a>`doOnError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([46](#notes-46))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([49](#notes-49))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([49](#notes-49))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([47](#notes-47))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
+<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
 <a name='doOnSubscribe'></a>`doOnSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([49](#notes-49))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([49](#notes-49))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([52](#notes-52))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
 <a name='doOnTerminate'></a>`doOnTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([53](#notes-53))</sup>|
+<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([56](#notes-56))</sup>|
 <a name='error'></a>`error`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
-<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([58](#notes-58))</sup>|
-<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([60](#notes-60))</sup>|
-<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|
+<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
+<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([61](#notes-61))</sup>|
+<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([63](#notes-63))</sup>|
+<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|
 <a name='flatMap'></a>`flatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='flatMapCompletable'></a>`flatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([61](#notes-61))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([63](#notes-63))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([64](#notes-64))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapSingleElement'></a>`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([65](#notes-65))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([66](#notes-66))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|
-<a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([68](#notes-68))</sup>|
+<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([64](#notes-64))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([66](#notes-66))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapSingleElement'></a>`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([68](#notes-68))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|
+<a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|
 <a name='fromAction'></a>`fromAction`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromArray'></a>`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='fromArray'></a>`fromArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
 <a name='fromCallable'></a>`fromCallable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromCompletable'></a>`fromCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|
+<a name='fromCompletable'></a>`fromCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always error.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([76](#notes-76))</sup>|
 <a name='fromCompletionStage'></a>`fromCompletionStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromFuture'></a>`fromFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromIterable'></a>`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
-<a name='fromMaybe'></a>`fromMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromObservable'></a>`fromObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromOptional'></a>`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='fromIterable'></a>`fromIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
+<a name='fromMaybe'></a>`fromMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([76](#notes-76))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromObservable'></a>`fromObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([76](#notes-76))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromOptional'></a>`fromOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
 <a name='fromPublisher'></a>`fromPublisher`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='fromRunnable'></a>`fromRunnable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromSingle'></a>`fromSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([73](#notes-73))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='fromStream'></a>`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
+<a name='fromSingle'></a>`fromSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use wrap().'>([76](#notes-76))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='fromStream'></a>`fromStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([72](#notes-72))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item. Use just().'>([73](#notes-73))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
 <a name='fromSupplier'></a>`fromSupplier`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='generate'></a>`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([74](#notes-74))</sup>|
-<a name='groupBy'></a>`groupBy`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to group.'>([76](#notes-76))</sup>|
-<a name='groupJoin'></a>`groupJoin`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([77](#notes-77))</sup>|
+<a name='generate'></a>`generate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([77](#notes-77))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([77](#notes-77))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromSupplier().'>([77](#notes-77))</sup>|
+<a name='groupBy'></a>`groupBy`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to group.'>([79](#notes-79))</sup>|
+<a name='groupJoin'></a>`groupJoin`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([80](#notes-80))</sup>|
 <a name='hide'></a>`hide`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='ignoreElement'></a>`ignoreElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([78](#notes-78))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='ignoreElements'></a>`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([79](#notes-79))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='interval'></a>`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|
-<a name='intervalRange'></a>`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([80](#notes-80))</sup>|
-<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='join'></a>`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([81](#notes-81))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([81](#notes-81))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([77](#notes-77))</sup>|
+<a name='ignoreElement'></a>`ignoreElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([81](#notes-81))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElements().'>([81](#notes-81))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='ignoreElements'></a>`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='interval'></a>`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|
+<a name='intervalRange'></a>`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|
+<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='join'></a>`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([80](#notes-80))</sup>|
 <a name='just'></a>`just`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
-<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([58](#notes-58))</sup>|
-<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([60](#notes-60))</sup>|
-<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|
+<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
+<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([61](#notes-61))</sup>|
+<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([63](#notes-63))</sup>|
+<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|
 <a name='lift'></a>`lift`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='map'></a>`map`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='mapOptional'></a>`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
@@ -144,100 +144,100 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='mergeWith'></a>`mergeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='never'></a>`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='observeOn'></a>`observeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([82](#notes-82))</sup>|
-<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
-<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
-<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
+<a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([85](#notes-85))</sup>|
+<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
+<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
+<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
 <a name='onErrorComplete'></a>`onErrorComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeNext'></a>`onErrorResumeNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeWith'></a>`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorReturn'></a>`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='onErrorReturnItem'></a>`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
 <a name='onTerminateDetach'></a>`onTerminateDetach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='parallel'></a>`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([83](#notes-83))</sup>|
-<a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
-<a name='range'></a>`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
-<a name='rangeLong'></a>`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([71](#notes-71))</sup>|
-<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([48](#notes-48))</sup>|
-<a name='reduce'></a>`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
-<a name='reduceWith'></a>`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
+<a name='parallel'></a>`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|
+<a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
+<a name='range'></a>`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
+<a name='rangeLong'></a>`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
+<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
+<a name='reduce'></a>`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
+<a name='reduceWith'></a>`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='repeat'></a>`repeat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='repeatUntil'></a>`repeatUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='repeatWhen'></a>`repeatWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='replay'></a>`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
+<a name='replay'></a>`replay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
 <a name='retry'></a>`retry`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='retryWhen'></a>`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
-<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
-<a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([89](#notes-89))</sup>|
+<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
+<a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
-<a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([90](#notes-90))</sup>|
-<a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([85](#notes-85))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([86](#notes-86))</sup>|
-<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([38](#notes-38))</sup>|
-<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([58](#notes-58))</sup>|
-<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([60](#notes-60))</sup>|
-<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([59](#notes-59))</sup>|
-<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
-<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
-<a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([91](#notes-91))</sup>|
-<a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([75](#notes-75))</sup>|
+<a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|
+<a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
+<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
+<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([61](#notes-61))</sup>|
+<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([63](#notes-63))</sup>|
+<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|
+<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
+<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
+<a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|
+<a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|
 <a name='startWith'></a>`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='startWithArray'></a>`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([93](#notes-93))</sup>|
-<a name='startWithItem'></a>`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([94](#notes-94))</sup>|
-<a name='startWithIterable'></a>`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([95](#notes-95))</sup>|
+<a name='startWithArray'></a>`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([96](#notes-96))</sup>|
+<a name='startWithItem'></a>`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([97](#notes-97))</sup>|
+<a name='startWithIterable'></a>`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([98](#notes-98))</sup>|
 <a name='subscribe'></a>`subscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='subscribeOn'></a>`subscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='subscribeWith'></a>`subscribeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='switchIfEmpty'></a>`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use defaultIfEmpty().'>([96](#notes-96))</sup>|
-<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchIfEmpty'></a>`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use defaultIfEmpty().'>([99](#notes-99))</sup>|
+<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
-<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([56](#notes-56))</sup>|
+<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
+<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
 <a name='takeUntil'></a>`takeUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='takeWhile'></a>`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([92](#notes-92))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='takeWhile'></a>`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='test'></a>`test`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
-<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
 <a name='timeout'></a>`timeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='timer'></a>`timer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([37](#notes-37))</sup>|
+<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
 <a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([98](#notes-98))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([101](#notes-101))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([101](#notes-101))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toFuture'></a>`toFuture`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toList'></a>`toList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='toMap'></a>`toMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
-<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toMaybe'></a>`toMaybe`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([103](#notes-103))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstElement.'>([103](#notes-103))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toMultimap'></a>`toMultimap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
-<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([101](#notes-101))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([101](#notes-101))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([102](#notes-102))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([102](#notes-102))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([103](#notes-103))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([99](#notes-99))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toObservable'></a>`toObservable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingle'></a>`toSingle`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([104](#notes-104))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstOrError.'>([104](#notes-104))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='toSingleDefault'></a>`toSingleDefault`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([105](#notes-105))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use first.'>([105](#notes-105))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use defaultIfEmpty().'>([106](#notes-106))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toSortedList'></a>`toSortedList`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element to collect. Use map() to transform into a list/collection.'>([13](#notes-13))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='One element to collect. Use map() to transform into a list/collection.'>([14](#notes-14))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a collection.'>([15](#notes-15))</sup>|
 <a name='unsafeCreate'></a>`unsafeCreate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='unsubscribeOn'></a>`unsubscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='using'></a>`using`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='window'></a>`window`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([104](#notes-104))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([105](#notes-105))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a nested source.'>([106](#notes-106))</sup>|
+<a name='window'></a>`window`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([107](#notes-107))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use map() to transform into a nested source.'>([108](#notes-108))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to bring in a nested source.'>([109](#notes-109))</sup>|
 <a name='withLatestFrom'></a>`withLatestFrom`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one element per source. Use zip().'>([16](#notes-16))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use merge().'>([17](#notes-17))</sup>|
-<a name='wrap'></a>`wrap`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromPublisher().'>([107](#notes-107))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([108](#notes-108))</sup>|
-<a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([109](#notes-109))</sup>|
-<a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([110](#notes-110))</sup>|
-<a name='total'></a>**237 operators** | **215** | **209** | **113** | **97** | **78** |
+<a name='wrap'></a>`wrap`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use fromPublisher().'>([110](#notes-110))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([111](#notes-111))</sup>|
+<a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([112](#notes-112))</sup>|
+<a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([113](#notes-113))</sup>|
+<a name='total'></a>**237 operators** | **215** | **209** | **115** | **100** | **78** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -269,87 +269,90 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='notes-27'></a><sup>27</sup> Always empty thus no items to map.<br/>
 <a name='notes-28'></a><sup>28</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use [`concatMapCompletable`](#concatMapCompletable).<br/>
 <a name='notes-29'></a><sup>29</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMap`](#concatMap).<br/>
-<a name='notes-30'></a><sup>30</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
-<a name='notes-31'></a><sup>31</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).<br/>
-<a name='notes-32'></a><sup>32</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).<br/>
-<a name='notes-33'></a><sup>33</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
-<a name='notes-34'></a><sup>34</sup> Never empty thus always 1.<br/>
-<a name='notes-35'></a><sup>35</sup> Always empty thus always 0.<br/>
-<a name='notes-36'></a><sup>36</sup> At most one item signaled so no subsequent items to work with.<br/>
-<a name='notes-37'></a><sup>37</sup> Always empty thus no items to work with.<br/>
-<a name='notes-38'></a><sup>38</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
-<a name='notes-39'></a><sup>39</sup> At most one item, always distinct.<br/>
-<a name='notes-40'></a><sup>40</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
-<a name='notes-41'></a><sup>41</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
-<a name='notes-42'></a><sup>42</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
-<a name='notes-43'></a><sup>43</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
-<a name='notes-44'></a><sup>44</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
-<a name='notes-45'></a><sup>45</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
-<a name='notes-46'></a><sup>46</sup> Use [`doOnEach()`](#doOnEach).<br/>
-<a name='notes-47'></a><sup>47</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
-<a name='notes-48'></a><sup>48</sup> Backpressure related and not supported outside `Flowable`.<br/>
-<a name='notes-49'></a><sup>49</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
-<a name='notes-50'></a><sup>50</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
-<a name='notes-51'></a><sup>51</sup> Always one item with index 0.<br/>
-<a name='notes-52'></a><sup>52</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
-<a name='notes-53'></a><sup>53</sup> Use [`complete()`](#complete).<br/>
-<a name='notes-54'></a><sup>54</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
-<a name='notes-55'></a><sup>55</sup> Always one item.<br/>
-<a name='notes-56'></a><sup>56</sup> At most one item, would be no-op.<br/>
-<a name='notes-57'></a><sup>57</sup> Always one item, would be no-op.<br/>
-<a name='notes-58'></a><sup>58</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
-<a name='notes-59'></a><sup>59</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
-<a name='notes-60'></a><sup>60</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
-<a name='notes-61'></a><sup>61</sup> Use [`flatMap()`](#flatMap).<br/>
-<a name='notes-62'></a><sup>62</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
-<a name='notes-63'></a><sup>63</sup> Use [`flatMap`](#flatMap).<br/>
-<a name='notes-64'></a><sup>64</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
-<a name='notes-65'></a><sup>65</sup> Use [`flatMapSingle`](#flatMapSingle).<br/>
-<a name='notes-66'></a><sup>66</sup> Use [`flatMapIterable()`](#flatMapIterable).<br/>
-<a name='notes-67'></a><sup>67</sup> Use [`flatMapStream()`](#flatMapStream).<br/>
-<a name='notes-68'></a><sup>68</sup> Use [`subscribe()`](#subscribe).<br/>
-<a name='notes-69'></a><sup>69</sup> At most one item. Use [`just()`](#just) or [`empty()`](#empty).<br/>
-<a name='notes-70'></a><sup>70</sup> Always one item. Use [`just()`](#just).<br/>
-<a name='notes-71'></a><sup>71</sup> Always empty. Use [`complete()`](#complete).<br/>
-<a name='notes-72'></a><sup>72</sup> Always error.<br/>
-<a name='notes-73'></a><sup>73</sup> Use [`wrap()`](#wrap).<br/>
-<a name='notes-74'></a><sup>74</sup> Use [`fromSupplier()`](#fromSupplier).<br/>
-<a name='notes-75'></a><sup>75</sup> At most one item.<br/>
-<a name='notes-76'></a><sup>76</sup> Always empty thus no items to group.<br/>
-<a name='notes-77'></a><sup>77</sup> Always empty thus no items to join.<br/>
-<a name='notes-78'></a><sup>78</sup> Use [`ignoreElements()`](#ignoreElements).<br/>
-<a name='notes-79'></a><sup>79</sup> Use [`ignoreElement()`](#ignoreElement).<br/>
-<a name='notes-80'></a><sup>80</sup> At most one item. Use [`timer()`](#timer).<br/>
-<a name='notes-81'></a><sup>81</sup> At most one item. Use [`zip()`](#zip)<br/>
-<a name='notes-82'></a><sup>82</sup> Always empty thus no items to filter.<br/>
-<a name='notes-83'></a><sup>83</sup> Needs backpressure thus not supported outside `Flowable`.<br/>
-<a name='notes-84'></a><sup>84</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.<br/>
-<a name='notes-85'></a><sup>85</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.<br/>
-<a name='notes-86'></a><sup>86</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.<br/>
-<a name='notes-87'></a><sup>87</sup> At most one item. Use [`just()`](#just).<br/>
-<a name='notes-88'></a><sup>88</sup> At most one item. Use [`map()`](#map).<br/>
-<a name='notes-89'></a><sup>89</sup> Always empty thus no items to reduce.<br/>
-<a name='notes-90'></a><sup>90</sup> At most one signal type.<br/>
-<a name='notes-91'></a><sup>91</sup> At most one item. Use [`takeUntil()`](#takeUntil).<br/>
-<a name='notes-92'></a><sup>92</sup> At most one item. Use [`filter()`](#filter).<br/>
-<a name='notes-93'></a><sup>93</sup> Use [`startWith()`](#startWith) and [`fromArray()`](#fromArray) of `Flowable` or `Observable`.<br/>
-<a name='notes-94'></a><sup>94</sup> Use [`startWith()`](#startWith) and [`just()`](#just) of another reactive type.<br/>
-<a name='notes-95'></a><sup>95</sup> Use [`startWith()`](#startWith) and [`fromIterable()`](#fromArray) of `Flowable` or `Observable`.<br/>
-<a name='notes-96'></a><sup>96</sup> Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
-<a name='notes-97'></a><sup>97</sup> At most one item. Use [`flatMap()`](#flatMap).<br/>
-<a name='notes-98'></a><sup>98</sup> Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).<br/>
-<a name='notes-99'></a><sup>99</sup> Would be no-op.<br/>
-<a name='notes-100'></a><sup>100</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
-<a name='notes-101'></a><sup>101</sup> Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).<br/>
-<a name='notes-102'></a><sup>102</sup> Use [`first`](#first), [`last`](#last) or [`single`](#single).<br/>
-<a name='notes-103'></a><sup>103</sup> Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
-<a name='notes-104'></a><sup>104</sup> Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a nested source.<br/>
-<a name='notes-105'></a><sup>105</sup> Use [`map()`](#map) to transform into a nested source.<br/>
-<a name='notes-106'></a><sup>106</sup> Always empty. Use [`andThen()`](#andThen) to bring in a nested source.<br/>
-<a name='notes-107'></a><sup>107</sup> Use [`fromPublisher()`](#fromPublisher).<br/>
-<a name='notes-108'></a><sup>108</sup> Use [`merge()`](#merge).<br/>
-<a name='notes-109'></a><sup>109</sup> Use [`mergeArray()`](#mergeArray).<br/>
-<a name='notes-110'></a><sup>110</sup> Use [`mergeWith()`](#mergeWith).<br/>
+<a name='notes-30'></a><sup>30</sup> At most one item to map. Use [`concatMap()`](#concatMap).<br/>
+<a name='notes-31'></a><sup>31</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
+<a name='notes-32'></a><sup>32</sup> Use [`concatMap`](#concatMap).<br/>
+<a name='notes-33'></a><sup>33</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).<br/>
+<a name='notes-34'></a><sup>34</sup> Use [`concatMap()`](#concatMap).<br/>
+<a name='notes-35'></a><sup>35</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).<br/>
+<a name='notes-36'></a><sup>36</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
+<a name='notes-37'></a><sup>37</sup> Never empty thus always 1.<br/>
+<a name='notes-38'></a><sup>38</sup> Always empty thus always 0.<br/>
+<a name='notes-39'></a><sup>39</sup> At most one item signaled so no subsequent items to work with.<br/>
+<a name='notes-40'></a><sup>40</sup> Always empty thus no items to work with.<br/>
+<a name='notes-41'></a><sup>41</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
+<a name='notes-42'></a><sup>42</sup> At most one item, always distinct.<br/>
+<a name='notes-43'></a><sup>43</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
+<a name='notes-44'></a><sup>44</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
+<a name='notes-45'></a><sup>45</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
+<a name='notes-46'></a><sup>46</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
+<a name='notes-47'></a><sup>47</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
+<a name='notes-48'></a><sup>48</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
+<a name='notes-49'></a><sup>49</sup> Use [`doOnEach()`](#doOnEach).<br/>
+<a name='notes-50'></a><sup>50</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
+<a name='notes-51'></a><sup>51</sup> Backpressure related and not supported outside `Flowable`.<br/>
+<a name='notes-52'></a><sup>52</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
+<a name='notes-53'></a><sup>53</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-54'></a><sup>54</sup> Always one item with index 0.<br/>
+<a name='notes-55'></a><sup>55</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
+<a name='notes-56'></a><sup>56</sup> Use [`complete()`](#complete).<br/>
+<a name='notes-57'></a><sup>57</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-58'></a><sup>58</sup> Always one item.<br/>
+<a name='notes-59'></a><sup>59</sup> At most one item, would be no-op.<br/>
+<a name='notes-60'></a><sup>60</sup> Always one item, would be no-op.<br/>
+<a name='notes-61'></a><sup>61</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
+<a name='notes-62'></a><sup>62</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-63'></a><sup>63</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-64'></a><sup>64</sup> Use [`flatMap()`](#flatMap).<br/>
+<a name='notes-65'></a><sup>65</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
+<a name='notes-66'></a><sup>66</sup> Use [`flatMap`](#flatMap).<br/>
+<a name='notes-67'></a><sup>67</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
+<a name='notes-68'></a><sup>68</sup> Use [`flatMapSingle`](#flatMapSingle).<br/>
+<a name='notes-69'></a><sup>69</sup> Use [`flatMapIterable()`](#flatMapIterable).<br/>
+<a name='notes-70'></a><sup>70</sup> Use [`flatMapStream()`](#flatMapStream).<br/>
+<a name='notes-71'></a><sup>71</sup> Use [`subscribe()`](#subscribe).<br/>
+<a name='notes-72'></a><sup>72</sup> At most one item. Use [`just()`](#just) or [`empty()`](#empty).<br/>
+<a name='notes-73'></a><sup>73</sup> Always one item. Use [`just()`](#just).<br/>
+<a name='notes-74'></a><sup>74</sup> Always empty. Use [`complete()`](#complete).<br/>
+<a name='notes-75'></a><sup>75</sup> Always error.<br/>
+<a name='notes-76'></a><sup>76</sup> Use [`wrap()`](#wrap).<br/>
+<a name='notes-77'></a><sup>77</sup> Use [`fromSupplier()`](#fromSupplier).<br/>
+<a name='notes-78'></a><sup>78</sup> At most one item.<br/>
+<a name='notes-79'></a><sup>79</sup> Always empty thus no items to group.<br/>
+<a name='notes-80'></a><sup>80</sup> Always empty thus no items to join.<br/>
+<a name='notes-81'></a><sup>81</sup> Use [`ignoreElements()`](#ignoreElements).<br/>
+<a name='notes-82'></a><sup>82</sup> Use [`ignoreElement()`](#ignoreElement).<br/>
+<a name='notes-83'></a><sup>83</sup> At most one item. Use [`timer()`](#timer).<br/>
+<a name='notes-84'></a><sup>84</sup> At most one item. Use [`zip()`](#zip)<br/>
+<a name='notes-85'></a><sup>85</sup> Always empty thus no items to filter.<br/>
+<a name='notes-86'></a><sup>86</sup> Needs backpressure thus not supported outside `Flowable`.<br/>
+<a name='notes-87'></a><sup>87</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `MaybeSubject`.<br/>
+<a name='notes-88'></a><sup>88</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `SingleSubject`.<br/>
+<a name='notes-89'></a><sup>89</sup> Connectable sources not supported outside `Flowable` and `Observable`. Use a `ConnectableSubject`.<br/>
+<a name='notes-90'></a><sup>90</sup> At most one item. Use [`just()`](#just).<br/>
+<a name='notes-91'></a><sup>91</sup> At most one item. Use [`map()`](#map).<br/>
+<a name='notes-92'></a><sup>92</sup> Always empty thus no items to reduce.<br/>
+<a name='notes-93'></a><sup>93</sup> At most one signal type.<br/>
+<a name='notes-94'></a><sup>94</sup> At most one item. Use [`takeUntil()`](#takeUntil).<br/>
+<a name='notes-95'></a><sup>95</sup> At most one item. Use [`filter()`](#filter).<br/>
+<a name='notes-96'></a><sup>96</sup> Use [`startWith()`](#startWith) and [`fromArray()`](#fromArray) of `Flowable` or `Observable`.<br/>
+<a name='notes-97'></a><sup>97</sup> Use [`startWith()`](#startWith) and [`just()`](#just) of another reactive type.<br/>
+<a name='notes-98'></a><sup>98</sup> Use [`startWith()`](#startWith) and [`fromIterable()`](#fromArray) of `Flowable` or `Observable`.<br/>
+<a name='notes-99'></a><sup>99</sup> Always empty. Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
+<a name='notes-100'></a><sup>100</sup> At most one item. Use [`flatMap()`](#flatMap).<br/>
+<a name='notes-101'></a><sup>101</sup> Use [`firstStage`](#firstStage), [`lastStage`](#lastStage) or [`singleStage`](#singleStage).<br/>
+<a name='notes-102'></a><sup>102</sup> Would be no-op.<br/>
+<a name='notes-103'></a><sup>103</sup> Use [`firstElement`](#firstElement), [`lastElement`](#lastElement) or [`singleElement`](#singleElement).<br/>
+<a name='notes-104'></a><sup>104</sup> Use [`firstOrError`](#firstOrError), [`lastOrError`](#lastOrError) or [`singleOrError`](#singleOrError).<br/>
+<a name='notes-105'></a><sup>105</sup> Use [`first`](#first), [`last`](#last) or [`single`](#single).<br/>
+<a name='notes-106'></a><sup>106</sup> Use [`defaultIfEmpty()`](#defaultIfEmpty).<br/>
+<a name='notes-107'></a><sup>107</sup> Use [`map()`](#map) and [`switchIfEmpty()`](#switchIfEmpty) to transform into a nested source.<br/>
+<a name='notes-108'></a><sup>108</sup> Use [`map()`](#map) to transform into a nested source.<br/>
+<a name='notes-109'></a><sup>109</sup> Always empty. Use [`andThen()`](#andThen) to bring in a nested source.<br/>
+<a name='notes-110'></a><sup>110</sup> Use [`fromPublisher()`](#fromPublisher).<br/>
+<a name='notes-111'></a><sup>111</sup> Use [`merge()`](#merge).<br/>
+<a name='notes-112'></a><sup>112</sup> Use [`mergeArray()`](#mergeArray).<br/>
+<a name='notes-113'></a><sup>113</sup> Use [`mergeWith()`](#mergeWith).<br/>
 
 #### Under development
 
@@ -359,26 +362,13 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 4. Single.concatArrayEagerDelayError()
 5. Single.concatDelayError()
 6. Completable.concatDelayError()
-7. Single.concatMap()
-8. Maybe.concatMapCompletable()
-9. Single.concatMapCompletable()
-10. Maybe.concatMapEager()
-11. Single.concatMapEager()
-12. Completable.concatMapEager()
-13. Maybe.concatMapEagerDelayError()
-14. Single.concatMapEagerDelayError()
-15. Completable.concatMapEagerDelayError()
-16. Maybe.concatMapMaybe()
-17. Single.concatMapMaybe()
-18. Maybe.concatMapSingle()
-19. Single.concatMapSingle()
-20. Single.mergeArray()
-21. Single.mergeArrayDelayError()
-22. Completable.onErrorReturn()
-23. Completable.onErrorReturnItem()
-24. Maybe.safeSubscribe()
-25. Single.safeSubscribe()
-26. Completable.safeSubscribe()
-27. Completable.sequenceEqual()
-28. Maybe.startWith()
-29. Single.startWith()
+7. Single.mergeArray()
+8. Single.mergeArrayDelayError()
+9. Completable.onErrorReturn()
+10. Completable.onErrorReturnItem()
+11. Maybe.safeSubscribe()
+12. Single.safeSubscribe()
+13. Completable.safeSubscribe()
+14. Completable.sequenceEqual()
+15. Maybe.startWith()
+16. Single.startWith()
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index b3ed8213d4..6754f65e7b 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -2828,12 +2828,13 @@ public final <R> Maybe<R> compose(@NonNull MaybeTransformer<? super T, ? extends
      * Returns a {@code Maybe} that is based on applying a specified function to the item emitted by the current {@code Maybe},
      * where that function returns a {@link MaybeSource}.
      * <p>
-     * <img width="640" height="356" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.png" alt="">
+     * <img width="640" height="216" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatMap.png" alt="">
+     * <p>
+     * Note that flatMap and concatMap for {@code Maybe} is the same operation.
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code concatMap} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
-     * <p>Note that flatMap and concatMap for {@code Maybe} is the same operation.
      * @param <R> the result value type
      * @param mapper
      *            a function that, when applied to the item emitted by the current {@code Maybe}, returns a {@code MaybeSource}
@@ -2845,8 +2846,63 @@ public final <R> Maybe<R> compose(@NonNull MaybeTransformer<? super T, ? extends
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public final <R> Maybe<R> concatMap(@NonNull Function<? super T, ? extends MaybeSource<? extends R>> mapper) {
-        Objects.requireNonNull(mapper, "mapper is null");
-        return RxJavaPlugins.onAssembly(new MaybeFlatten<>(this, mapper));
+        return flatMap(mapper);
+    }
+
+    /**
+     * Returns a {@link Completable} that completes based on applying a specified function to the item emitted by the
+     * current {@code Maybe}, where that function returns a {@code Completable}.
+     * <p>
+     * <img width="640" height="304" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatMapCompletable.png" alt="">
+     * <p>
+     * This operator is an alias for {@link #flatMapCompletable(Function)}.
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code concatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param mapper
+     *            a function that, when applied to the item emitted by the current {@code Maybe}, returns a
+     *            {@code Completable}
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code mapper} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Completable concatMapCompletable(@NonNull Function<? super T, ? extends CompletableSource> mapper) {
+        return flatMapCompletable(mapper);
+    }
+
+    /**
+     * Returns a {@code Maybe} based on applying a specified function to the item emitted by the
+     * current {@code Maybe}, where that function returns a {@link Single}.
+     * When this {@code Maybe} just completes the resulting {@code Maybe} completes as well.
+     * <p>
+     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatMapSingle.png" alt="">
+     * <p>
+     * This operator is an alias for {@link #flatMapSingleElement(Function)}.
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code concatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <R> the result value type
+     * @param mapper
+     *            a function that, when applied to the item emitted by the current {@code Maybe}, returns a
+     *            {@code Single}
+     * @return the new {@code Maybe} instance
+     * @throws NullPointerException if {@code mapper} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <R> Maybe<R> concatMapSingle(@NonNull Function<? super T, ? extends SingleSource<? extends R>> mapper) {
+        return flatMapSingleElement(mapper);
     }
 
     /**
@@ -3732,7 +3788,7 @@ public final <R> Flowable<R> flatMapPublisher(@NonNull Function<? super T, ? ext
      * current {@code Maybe}, where that function returns a {@code Single}.
      * When this {@code Maybe} completes a {@link NoSuchElementException} will be thrown.
      * <p>
-     * <img width="640" height="356" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle.png" alt="">
+     * <img width="640" height="346" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle3.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3759,7 +3815,7 @@ public final <R> Single<R> flatMapSingle(@NonNull Function<? super T, ? extends
      * current {@code Maybe}, where that function returns a {@link Single}.
      * When this {@code Maybe} just completes the resulting {@code Maybe} completes as well.
      * <p>
-     * <img width="640" height="356" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle.png" alt="">
+     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapSingleElement} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3787,7 +3843,7 @@ public final <R> Maybe<R> flatMapSingleElement(@NonNull Function<? super T, ? ex
      * Returns a {@link Completable} that completes based on applying a specified function to the item emitted by the
      * current {@code Maybe}, where that function returns a {@code Completable}.
      * <p>
-     * <img width="640" height="267" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapCompletable.png" alt="">
+     * <img width="640" height="303" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapCompletable3.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 81b0aaaffe..0a1d872b14 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -2278,6 +2278,86 @@ public final <U> Single<U> cast(@NonNull Class<? extends U> clazz) {
         return map(Functions.castFunction(clazz));
     }
 
+    /**
+     * Returns a {@code Single} that is based on applying a specified function to the item emitted by the current {@code Single},
+     * where that function returns a {@link SingleSource}.
+     * <p>
+     * <img width="640" height="313" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatMap.png" alt="">
+     * <p>
+     * The operator is an alias for {@link #flatMap(Function)}
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code concatMap} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <R> the result value type
+     * @param mapper
+     *            a function that, when applied to the item emitted by the current {@code Single}, returns a {@code SingleSource}
+     * @return the new {@code Single} returned from {@code mapper} when applied to the item emitted by the current {@code Single}
+     * @throws NullPointerException if {@code mapper} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <R> Single<R> concatMap(@NonNull Function<? super T, ? extends SingleSource<? extends R>> mapper) {
+        Objects.requireNonNull(mapper, "mapper is null");
+        return RxJavaPlugins.onAssembly(new SingleFlatMap<>(this, mapper));
+    }
+
+    /**
+     * Returns a {@link Completable} that completes based on applying a specified function to the item emitted by the
+     * current {@code Single}, where that function returns a {@link CompletableSource}.
+     * <p>
+     * <img width="640" height="298" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatMapCompletable.png" alt="">
+     * <p>
+     * The operator is an alias for {@link #flatMapCompletable(Function)}.
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code concatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param mapper
+     *            a function that, when applied to the item emitted by the current {@code Single}, returns a
+     *            {@code CompletableSource}
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code mapper} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Completable concatMapCompletable(@NonNull Function<? super T, ? extends CompletableSource> mapper) {
+        return flatMapCompletable(mapper);
+    }
+
+    /**
+     * Returns a {@link Maybe} that is based on applying a specified function to the item emitted by the current {@code Single},
+     * where that function returns a {@link MaybeSource}.
+     * <p>
+     * <img width="640" height="254" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatMapMaybe.png" alt="">
+     * <p>
+     * The operator is an alias for {@link #flatMapMaybe(Function)}.
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code concatMapMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <R> the result value type
+     * @param mapper
+     *            a function that, when applied to the item emitted by the current {@code Single}, returns a {@code MaybeSource}
+     * @return the new {@code Maybe} returned from {@code mapper} when applied to the item emitted by the current {@code Single}
+     * @throws NullPointerException if {@code mapper} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <R> Maybe<R> concatMapMaybe(@NonNull Function<? super T, ? extends MaybeSource<? extends R>> mapper) {
+        return flatMapMaybe(mapper);
+    }
+
     /**
      * Returns a {@link Flowable} that emits the item emitted by the current {@code Single}, then the item emitted by the
      * specified {@link SingleSource}.
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapCompletableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapCompletableTest.java
new file mode 100644
index 0000000000..e902bbf4df
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapCompletableTest.java
@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeConcatMapCompletableTest extends RxJavaTest {
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Maybe.just(1).concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer v) throws Exception {
+                return Completable.complete();
+            }
+        }));
+    }
+
+    @Test
+    public void mapperThrows() {
+        Maybe.just(1)
+        .concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer v) throws Exception {
+                throw new TestException();
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void mapperReturnsNull() {
+        Maybe.just(1)
+        .concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer v) throws Exception {
+                return null;
+            }
+        })
+        .test()
+        .assertFailure(NullPointerException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapSingleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapSingleTest.java
new file mode 100644
index 0000000000..2626b18e26
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapSingleTest.java
@@ -0,0 +1,142 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeConcatMapSingleTest extends RxJavaTest {
+    @Test
+    public void flatMapSingleElementValue() {
+        Maybe.just(1).concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                if (integer == 1) {
+                    return Single.just(2);
+                }
+
+                return Single.just(1);
+            }
+        })
+            .test()
+            .assertResult(2);
+    }
+
+    @Test
+    public void flatMapSingleElementValueDifferentType() {
+        Maybe.just(1).concatMapSingle(new Function<Integer, SingleSource<String>>() {
+            @Override public SingleSource<String> apply(final Integer integer) throws Exception {
+                if (integer == 1) {
+                    return Single.just("2");
+                }
+
+                return Single.just("1");
+            }
+        })
+            .test()
+            .assertResult("2");
+    }
+
+    @Test
+    public void flatMapSingleElementValueNull() {
+        Maybe.just(1).concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                return null;
+            }
+        })
+            .to(TestHelper.<Integer>testConsumer())
+            .assertNoValues()
+            .assertError(NullPointerException.class)
+            .assertErrorMessage("The mapper returned a null SingleSource");
+    }
+
+    @Test
+    public void flatMapSingleElementValueErrorThrown() {
+        Maybe.just(1).concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                throw new RuntimeException("something went terribly wrong!");
+            }
+        })
+            .to(TestHelper.<Integer>testConsumer())
+            .assertNoValues()
+            .assertError(RuntimeException.class)
+            .assertErrorMessage("something went terribly wrong!");
+    }
+
+    @Test
+    public void flatMapSingleElementError() {
+        RuntimeException exception = new RuntimeException("test");
+
+        Maybe.error(exception).concatMapSingle(new Function<Object, SingleSource<Object>>() {
+            @Override public SingleSource<Object> apply(final Object integer) throws Exception {
+                return Single.just(new Object());
+            }
+        })
+            .test()
+            .assertError(exception);
+    }
+
+    @Test
+    public void flatMapSingleElementEmpty() {
+        Maybe.<Integer>empty().concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                return Single.just(2);
+            }
+        })
+            .test()
+            .assertNoValues()
+            .assertResult();
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Maybe.just(1).concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                return Single.just(2);
+            }
+        }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeMaybe(new Function<Maybe<Integer>, Maybe<Integer>>() {
+            @Override
+            public Maybe<Integer> apply(Maybe<Integer> m) throws Exception {
+                return m.concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+                    @Override
+                    public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                        return Single.just(2);
+                    }
+                });
+            }
+        });
+    }
+
+    @Test
+    public void singleErrors() {
+        Maybe.just(1)
+        .concatMapSingle(new Function<Integer, SingleSource<Integer>>() {
+                    @Override
+                    public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                        return Single.error(new TestException());
+                    }
+                })
+        .test()
+        .assertFailure(TestException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapTest.java
new file mode 100644
index 0000000000..7504117df4
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatMapTest.java
@@ -0,0 +1,101 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeConcatMapTest extends RxJavaTest {
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Maybe.just(1).concatMap(new Function<Integer, MaybeSource<Integer>>() {
+            @Override
+            public MaybeSource<Integer> apply(Integer v) throws Exception {
+                return Maybe.just(2);
+            }
+        }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeMaybe(new Function<Maybe<Integer>, MaybeSource<Integer>>() {
+            @Override
+            public MaybeSource<Integer> apply(Maybe<Integer> v) throws Exception {
+                return v.concatMap(new Function<Integer, MaybeSource<Integer>>() {
+                    @Override
+                    public MaybeSource<Integer> apply(Integer v) throws Exception {
+                        return Maybe.just(2);
+                    }
+                });
+            }
+        });
+    }
+
+    @Test
+    public void mainError() {
+        Maybe.<Integer>error(new TestException())
+        .concatMap(new Function<Integer, MaybeSource<Integer>>() {
+                    @Override
+                    public MaybeSource<Integer> apply(Integer v) throws Exception {
+                        return Maybe.just(2);
+                    }
+                })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void mainEmpty() {
+        Maybe.<Integer>empty()
+        .concatMap(new Function<Integer, MaybeSource<Integer>>() {
+                    @Override
+                    public MaybeSource<Integer> apply(Integer v) throws Exception {
+                        return Maybe.just(2);
+                    }
+                })
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void mapperThrows() {
+        Maybe.just(1)
+        .concatMap(new Function<Integer, MaybeSource<Integer>>() {
+                    @Override
+                    public MaybeSource<Integer> apply(Integer v) throws Exception {
+                        throw new TestException();
+                    }
+                })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void mapperReturnsNull() {
+        Maybe.just(1)
+        .concatMap(new Function<Integer, MaybeSource<Integer>>() {
+                    @Override
+                    public MaybeSource<Integer> apply(Integer v) throws Exception {
+                        return null;
+                    }
+                })
+        .test()
+        .assertFailure(NullPointerException.class);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapCompletableTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapCompletableTest.java
new file mode 100644
index 0000000000..1a160f6465
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapCompletableTest.java
@@ -0,0 +1,114 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleConcatMapCompletableTest extends RxJavaTest {
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Single.just(1).concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer v) throws Exception {
+                return Completable.complete();
+            }
+        }));
+    }
+
+    @Test
+    public void normal() {
+        final boolean[] b = { false };
+
+        Single.just(1)
+        .concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer t) throws Exception {
+                return Completable.complete().doOnComplete(new Action() {
+                    @Override
+                    public void run() throws Exception {
+                        b[0] = true;
+                    }
+                });
+            }
+        })
+        .test()
+        .assertResult();
+
+        assertTrue(b[0]);
+    }
+
+    @Test
+    public void error() {
+        final boolean[] b = { false };
+
+        Single.<Integer>error(new TestException())
+        .concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer t) throws Exception {
+                return Completable.complete().doOnComplete(new Action() {
+                    @Override
+                    public void run() throws Exception {
+                        b[0] = true;
+                    }
+                });
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+
+        assertFalse(b[0]);
+    }
+
+    @Test
+    public void mapperThrows() {
+        final boolean[] b = { false };
+
+        Single.just(1)
+        .concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer t) throws Exception {
+                throw new TestException();
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+
+        assertFalse(b[0]);
+    }
+
+    @Test
+    public void mapperReturnsNull() {
+        final boolean[] b = { false };
+
+        Single.just(1)
+        .concatMapCompletable(new Function<Integer, Completable>() {
+            @Override
+            public Completable apply(Integer t) throws Exception {
+                return null;
+            }
+        })
+        .test()
+        .assertFailure(NullPointerException.class);
+
+        assertFalse(b[0]);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapMaybeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapMaybeTest.java
new file mode 100644
index 0000000000..dd25e7a53f
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapMaybeTest.java
@@ -0,0 +1,141 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleConcatMapMaybeTest extends RxJavaTest {
+    @Test
+    public void concatMapMaybeValue() {
+        Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+            @Override public MaybeSource<Integer> apply(final Integer integer) throws Exception {
+                if (integer == 1) {
+                    return Maybe.just(2);
+                }
+
+                return Maybe.just(1);
+            }
+        })
+            .test()
+            .assertResult(2);
+    }
+
+    @Test
+    public void concatMapMaybeValueDifferentType() {
+        Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<String>>() {
+            @Override public MaybeSource<String> apply(final Integer integer) throws Exception {
+                if (integer == 1) {
+                    return Maybe.just("2");
+                }
+
+                return Maybe.just("1");
+            }
+        })
+            .test()
+            .assertResult("2");
+    }
+
+    @Test
+    public void concatMapMaybeValueNull() {
+        Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+            @Override public MaybeSource<Integer> apply(final Integer integer) throws Exception {
+                return null;
+            }
+        })
+            .to(TestHelper.<Integer>testConsumer())
+            .assertNoValues()
+            .assertError(NullPointerException.class)
+            .assertErrorMessage("The mapper returned a null MaybeSource");
+    }
+
+    @Test
+    public void concatMapMaybeValueErrorThrown() {
+        Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+            @Override public MaybeSource<Integer> apply(final Integer integer) throws Exception {
+                throw new RuntimeException("something went terribly wrong!");
+            }
+        })
+            .to(TestHelper.<Integer>testConsumer())
+            .assertNoValues()
+            .assertError(RuntimeException.class)
+            .assertErrorMessage("something went terribly wrong!");
+    }
+
+    @Test
+    public void concatMapMaybeError() {
+        RuntimeException exception = new RuntimeException("test");
+
+        Single.error(exception).concatMapMaybe(new Function<Object, MaybeSource<Object>>() {
+            @Override public MaybeSource<Object> apply(final Object integer) throws Exception {
+                return Maybe.just(new Object());
+            }
+        })
+            .test()
+            .assertError(exception);
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+            @Override
+            public MaybeSource<Integer> apply(Integer v) throws Exception {
+                return Maybe.just(1);
+            }
+        }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingleToMaybe(new Function<Single<Integer>, MaybeSource<Integer>>() {
+            @Override
+            public MaybeSource<Integer> apply(Single<Integer> v) throws Exception {
+                return v.concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+                    @Override
+                    public MaybeSource<Integer> apply(Integer v) throws Exception {
+                        return Maybe.just(1);
+                    }
+                });
+            }
+        });
+    }
+
+    @Test
+    public void mapsToError() {
+        Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+            @Override
+            public MaybeSource<Integer> apply(Integer v) throws Exception {
+                return Maybe.error(new TestException());
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void mapsToEmpty() {
+        Single.just(1).concatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
+            @Override
+            public MaybeSource<Integer> apply(Integer v) throws Exception {
+                return Maybe.empty();
+            }
+        })
+        .test()
+        .assertResult();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapTest.java
new file mode 100644
index 0000000000..b0b5af17a6
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatMapTest.java
@@ -0,0 +1,132 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleConcatMapTest extends RxJavaTest {
+
+    @Test
+    public void concatMapValue() {
+        Single.just(1).concatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                if (integer == 1) {
+                    return Single.just(2);
+                }
+
+                return Single.just(1);
+            }
+        })
+            .test()
+            .assertResult(2);
+    }
+
+    @Test
+    public void concatMapValueDifferentType() {
+        Single.just(1).concatMap(new Function<Integer, SingleSource<String>>() {
+            @Override public SingleSource<String> apply(final Integer integer) throws Exception {
+                if (integer == 1) {
+                    return Single.just("2");
+                }
+
+                return Single.just("1");
+            }
+        })
+            .test()
+            .assertResult("2");
+    }
+
+    @Test
+    public void concatMapValueNull() {
+        Single.just(1).concatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                return null;
+            }
+        })
+        .to(TestHelper.<Integer>testConsumer())
+            .assertNoValues()
+            .assertError(NullPointerException.class)
+            .assertErrorMessage("The single returned by the mapper is null");
+    }
+
+    @Test
+    public void concatMapValueErrorThrown() {
+        Single.just(1).concatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
+                throw new RuntimeException("something went terribly wrong!");
+            }
+        })
+            .to(TestHelper.<Integer>testConsumer())
+            .assertNoValues()
+            .assertError(RuntimeException.class)
+            .assertErrorMessage("something went terribly wrong!");
+    }
+
+    @Test
+    public void concatMapError() {
+        RuntimeException exception = new RuntimeException("test");
+
+        Single.error(exception).concatMap(new Function<Object, SingleSource<Object>>() {
+            @Override public SingleSource<Object> apply(final Object integer) throws Exception {
+                return Single.just(new Object());
+            }
+        })
+            .test()
+            .assertError(exception);
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Single.just(1).concatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                return Single.just(2);
+            }
+        }));
+    }
+
+    @Test
+    public void mappedSingleOnError() {
+        Single.just(1).concatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                return Single.error(new TestException());
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingle(new Function<Single<Object>, SingleSource<Object>>() {
+            @Override
+            public SingleSource<Object> apply(Single<Object> s)
+                    throws Exception {
+                return s.concatMap(new Function<Object, SingleSource<? extends Object>>() {
+                    @Override
+                    public SingleSource<? extends Object> apply(Object v)
+                            throws Exception {
+                        return Single.just(v);
+                    }
+                });
+            }
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index a0ba3e52e4..0e2c0ada16 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -240,10 +240,16 @@ static String findNotes(String clazzName, String operatorName) {
             "    C concatMapCompletableDelayError       Always empty thus no items to map.",
             "  MS  concatMapDelayError                  Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMap`](#concatMap).",
             "    C concatMapDelayError                  Always empty thus no items to map.",
+            "  MS  concatMapEager                       At most one item to map. Use [`concatMap()`](#concatMap).",
+            "    C concatMapEager                       Always empty thus no items to map.",
+            "  MS  concatMapEagerDelayError             At most one item to map. Use [`concatMap()`](#concatMap).",
+            "    C concatMapEagerDelayError             Always empty thus no items to map.",
             "    C concatMapIterable                    Always empty thus no items to map.",
+            "  M   concatMapMaybe                       Use [`concatMap`](#concatMap).",
             "    C concatMapMaybe                       Always empty thus no items to map.",
             "  MS  concatMapMaybeDelayError             Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).",
             "    C concatMapMaybeDelayError             Always empty thus no items to map.",
+            "   S  concatMapSingle                      Use [`concatMap()`](#concatMap).",
             "    C concatMapSingle                      Always empty thus no items to map.",
             "  MS  concatMapSingleDelayError            Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).",
             "    C concatMapSingleDelayError            Always empty thus no items to map.",

From 9283700d3a04d495b0845f947ed119c1ed10ee94 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Mon, 27 Jan 2020 11:09:30 +0100
Subject: [PATCH 25/37] 3.x: Add various concatXDelayError operators (#6881)

---
 docs/Operator-Matrix.md                       |  34 ++---
 .../reactivex/rxjava3/core/Completable.java   |  91 +++++++++++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  68 ++++++++-
 .../io/reactivex/rxjava3/core/Single.java     | 144 +++++++++++++++++-
 .../CompletableConcatArrayDelayErrorTest.java |  43 ++++++
 .../CompletableConcatDelayErrorTest.java      |  82 ++++++++++
 .../MaybeConcatArrayEagerDelayErrorTest.java  |  34 +++++
 .../SingleConcatArrayDelayErrorTest.java      |  34 +++++
 .../SingleConcatArrayEagerDelayErrorTest.java |  34 +++++
 .../single/SingleConcatDelayErrorTest.java    |  58 +++++++
 .../io/reactivex/rxjava3/maybe/MaybeTest.java |  11 ++
 11 files changed, 605 insertions(+), 28 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatArrayDelayErrorTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatDelayErrorTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatArrayEagerDelayErrorTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayDelayErrorTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayEagerDelayErrorTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatDelayErrorTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index cd71558ddb..2ddd1cf21f 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -32,10 +32,10 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='compose'></a>`compose`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concat'></a>`concat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concatArray'></a>`concatArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='concatArrayDelayError'></a>`concatArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='concatArrayDelayError'></a>`concatArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concatArrayEager'></a>`concatArrayEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArray().'>([24](#notes-24))</sup>|
-<a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
-<a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
+<a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concatEager'></a>`concatEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use merge().'>([26](#notes-26))</sup>|
 <a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
@@ -237,7 +237,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([111](#notes-111))</sup>|
 <a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([112](#notes-112))</sup>|
 <a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([113](#notes-113))</sup>|
-<a name='total'></a>**237 operators** | **215** | **209** | **115** | **100** | **78** |
+<a name='total'></a>**237 operators** | **215** | **209** | **116** | **103** | **80** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -356,19 +356,13 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 
 #### Under development
 
-1. Single.concatArrayDelayError()
-2. Completable.concatArrayDelayError()
-3. Maybe.concatArrayEagerDelayError()
-4. Single.concatArrayEagerDelayError()
-5. Single.concatDelayError()
-6. Completable.concatDelayError()
-7. Single.mergeArray()
-8. Single.mergeArrayDelayError()
-9. Completable.onErrorReturn()
-10. Completable.onErrorReturnItem()
-11. Maybe.safeSubscribe()
-12. Single.safeSubscribe()
-13. Completable.safeSubscribe()
-14. Completable.sequenceEqual()
-15. Maybe.startWith()
-16. Single.startWith()
+1. Single.mergeArray()
+2. Single.mergeArrayDelayError()
+3. Completable.onErrorReturn()
+4. Completable.onErrorReturnItem()
+5. Maybe.safeSubscribe()
+6. Single.safeSubscribe()
+7. Completable.safeSubscribe()
+8. Completable.sequenceEqual()
+9. Maybe.startWith()
+10. Single.startWith()
diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 9febbd1204..253610ef80 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -202,6 +202,27 @@ public static Completable concatArray(@NonNull CompletableSource... sources) {
         return RxJavaPlugins.onAssembly(new CompletableConcatArray(sources));
     }
 
+    /**
+     * Returns a {@code Completable} which completes only when all sources complete, one after another.
+     * <p>
+     * <img width="640" height="322" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatArrayDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatArrayDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param sources the sources to concatenate
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SafeVarargs
+    public static Completable concatArrayDelayError(@NonNull CompletableSource... sources) {
+        return Flowable.fromArray(sources).concatMapCompletableDelayError(Functions.identity(), true, 2);
+    }
+
     /**
      * Returns a {@code Completable} which completes only when all sources complete, one after another.
      * <p>
@@ -273,6 +294,76 @@ public static Completable concat(@NonNull Publisher<@NonNull ? extends Completab
         return RxJavaPlugins.onAssembly(new CompletableConcat(sources, prefetch));
     }
 
+    /**
+     * Returns a {@code Completable} which completes only when all sources complete, one after another.
+     * <p>
+     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param sources the sources to concatenate
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static Completable concatDelayError(@NonNull Iterable<@NonNull ? extends CompletableSource> sources) {
+        return Flowable.fromIterable(sources).concatMapCompletableDelayError(Functions.identity());
+    }
+
+    /**
+     * Returns a {@code Completable} which completes only when all sources complete, one after another.
+     * <p>
+     * <img width="640" height="396" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatDelayError.p.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Completable} honors the backpressure of the downstream consumer
+     *  and expects the other {@link Publisher} to honor it as well.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param sources the sources to concatenate
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    @NonNull
+    public static Completable concatDelayError(@NonNull Publisher<@NonNull ? extends CompletableSource> sources) {
+        return concatDelayError(sources, 2);
+    }
+
+    /**
+     * Returns a {@code Completable} which completes only when all sources complete, one after another.
+     * <p>
+     * <img width="640" height="359" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatDelayError.pn.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Completable} honors the backpressure of the downstream consumer
+     *  and expects the other {@link Publisher} to honor it as well.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param sources the sources to concatenate
+     * @param prefetch the number of sources to prefetch from the sources
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code prefetch} is non-positive
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public static Completable concatDelayError(@NonNull Publisher<@NonNull ? extends CompletableSource> sources, int prefetch) {
+        return Flowable.fromPublisher(sources).concatMapCompletableDelayError(Functions.identity(), true, prefetch);
+    }
+
     /**
      * Provides an API (via a cold {@code Completable}) that bridges the reactive world with the callback-style world.
      * <p>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 6754f65e7b..ce02849d56 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -446,13 +446,42 @@ public static <T> Flowable<T> concatArrayDelayError(@NonNull MaybeSource<? exten
     public static <T> Flowable<T> concatArrayEager(@NonNull MaybeSource<? extends T>... sources) {
         return Flowable.fromArray(sources).concatMapEager((Function)MaybeToPublisher.instance());
     }
+    /**
+     * Concatenates a sequence of {@link MaybeSource} eagerly into a {@link Flowable} sequence.
+     * <p>
+     * Eager concatenation means that once an observer subscribes, this operator subscribes to all of the
+     * source {@code MaybeSource}s. The operator buffers the value emitted by these {@code MaybeSource}s and then drains them
+     * in order, each one after the previous one completes.
+     * <p>
+     * <img width="640" height="428" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatArrayEagerDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource}s that need to be eagerly concatenated
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    @SafeVarargs
+    public static <T> Flowable<T> concatArrayEagerDelayError(@NonNull MaybeSource<? extends T>... sources) {
+        return Flowable.fromArray(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), true);
+    }
 
     /**
      * Concatenates the {@link Iterable} sequence of {@link MaybeSource}s into a single sequence by subscribing to each {@code MaybeSource},
      * one after the other, one at a time and delays any errors till the all inner {@code MaybeSource}s terminate
      * as a {@link Flowable} sequence.
      * <p>
-     * <img width="640" height="469" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatDelayError.i.png" alt="">
+     * <img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatDelayError3.i.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -465,14 +494,12 @@ public static <T> Flowable<T> concatArrayEager(@NonNull MaybeSource<? extends T>
      * @return the new {@code Flowable} with the concatenating behavior
      * @throws NullPointerException if {@code sources} is {@code null}
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Flowable<T> concatDelayError(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources) {
-        Objects.requireNonNull(sources, "sources is null");
-        return Flowable.fromIterable(sources).concatMapDelayError((Function)MaybeToPublisher.instance());
+        return Flowable.fromIterable(sources).concatMapMaybeDelayError(Functions.identity());
     }
 
     /**
@@ -493,13 +520,42 @@ public static <T> Flowable<T> concatDelayError(@NonNull Iterable<@NonNull ? exte
      * @return the new {@code Flowable} with the concatenating behavior
      * @throws NullPointerException if {@code sources} is {@code null}
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources) {
-        return Flowable.fromPublisher(sources).concatMapDelayError((Function)MaybeToPublisher.instance());
+        return Flowable.fromPublisher(sources).concatMapMaybeDelayError(Functions.identity());
+    }
+    /**
+     * Concatenates the {@link Publisher} sequence of {@link MaybeSource}s into a single sequence by subscribing to each inner {@code MaybeSource},
+     * one after the other, one at a time and delays any errors till the all inner and the outer {@code Publisher} terminate
+     * as a {@link Flowable} sequence.
+     * <p>
+     * <img width="640" height="299" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatDelayError.pn.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>{@code concatDelayError} fully supports backpressure.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the common element base type
+     * @param sources the {@code Publisher} sequence of {@code MaybeSource}s
+     * @param prefetch The number of upstream items to prefetch so that fresh items are
+     *                 ready to be mapped when a previous {@code MaybeSource} terminates.
+     *                 The operator replenishes after half of the prefetch amount has been consumed
+     *                 and turned into {@code MaybeSource}s.
+     * @return the new {@code Flowable} with the concatenating behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code prefetch} is non-positive
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources, int prefetch) {
+        return Flowable.fromPublisher(sources).concatMapMaybeDelayError(Functions.identity(), true, prefetch);
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 0a1d872b14..9f5c3446c5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -406,10 +406,35 @@ public static <T> Flowable<T> concat(
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @SafeVarargs
     public static <T> Flowable<T> concatArray(@NonNull SingleSource<? extends T>... sources) {
-        return RxJavaPlugins.onAssembly(new FlowableConcatMap(Flowable.fromArray(sources), SingleInternalHelper.toFlowable(), 2, ErrorMode.BOUNDARY));
+        return Flowable.fromArray(sources).concatMap(SingleInternalHelper.toFlowable(), 2);
+    }
+
+    /**
+     * Concatenate the single values, in a non-overlapping fashion, of the {@link SingleSource}s provided in
+     * an array.
+     * <p>
+     * <img width="640" height="408" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatArrayDelayError.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@link Flowable} honors the backpressure of the downstream consumer.</dd>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code concatArrayDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources the array of {@code SingleSource} instances
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SafeVarargs
+    public static <T> Flowable<T> concatArrayDelayError(@NonNull SingleSource<? extends T>... sources) {
+        return Flowable.fromArray(sources).concatMapDelayError(SingleInternalHelper.toFlowable(), true, 2);
     }
 
     /**
@@ -440,6 +465,35 @@ public static <T> Flowable<T> concatArrayEager(@NonNull SingleSource<? extends T
         return Flowable.fromArray(sources).concatMapEager(SingleInternalHelper.toFlowable());
     }
 
+    /**
+     * Concatenates a sequence of {@link SingleSource} eagerly into a single stream of values.
+     * <p>
+     * <img width="640" height="426" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatArrayEagerDelayError.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * source {@code SingleSource}s. The operator buffers the value emitted by these {@code SingleSource}s and then drains them
+     * in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code SingleSource}s that need to be eagerly concatenated
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SafeVarargs
+    public static <T> Flowable<T> concatArrayEagerDelayError(@NonNull SingleSource<? extends T>... sources) {
+        return Flowable.fromArray(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), true);
+    }
+
     /**
      * Concatenates a {@link Publisher} sequence of {@link SingleSource}s eagerly into a single stream of values.
      * <p>
@@ -469,6 +523,92 @@ public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends
         return Flowable.fromPublisher(sources).concatMapEager(SingleInternalHelper.toFlowable());
     }
 
+    /**
+     * Concatenates the {@link Iterable} sequence of {@link SingleSource}s into a single sequence by subscribing to each {@code SingleSource},
+     * one after the other, one at a time and delays any errors till the all inner {@code SingleSource}s terminate
+     * as a {@link Flowable} sequence.
+     * <p>
+     * <img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatDelayError.i.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the common element base type
+     * @param sources the {@code Iterable} sequence of {@code SingleSource}s
+     * @return the new {@code Flowable} with the concatenating behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatDelayError(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources) {
+        return Flowable.fromIterable(sources).concatMapSingleDelayError(Functions.identity());
+    }
+
+    /**
+     * Concatenates the {@link Publisher} sequence of {@link SingleSource}s into a single sequence by subscribing to each inner {@code SingleSource},
+     * one after the other, one at a time and delays any errors till the all inner and the outer {@code Publisher} terminate
+     * as a {@link Flowable} sequence.
+     * <p>
+     * <img width="640" height="345" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatDelayError.p.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>{@code concatDelayError} fully supports backpressure.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the common element base type
+     * @param sources the {@code Publisher} sequence of {@code SingleSource}s
+     * @return the new {@code Flowable} with the concatenating behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
+        return Flowable.fromPublisher(sources).concatMapSingleDelayError(Functions.identity());
+    }
+
+    /**
+     * Concatenates the {@link Publisher} sequence of {@link SingleSource}s into a single sequence by subscribing to each inner {@code SingleSource},
+     * one after the other, one at a time and delays any errors till the all inner and the outer {@code Publisher} terminate
+     * as a {@link Flowable} sequence.
+     * <p>
+     * <img width="640" height="299" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatDelayError.pn.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>{@code concatDelayError} fully supports backpressure.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the common element base type
+     * @param sources the {@code Publisher} sequence of {@code SingleSource}s
+     * @param prefetch The number of upstream items to prefetch so that fresh items are
+     *                 ready to be mapped when a previous {@code SingleSource} terminates.
+     *                 The operator replenishes after half of the prefetch amount has been consumed
+     *                 and turned into {@code SingleSource}s.
+     * @return the new {@code Flowable} with the concatenating behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code prefetch} is non-positive
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources, int prefetch) {
+        return Flowable.fromPublisher(sources).concatMapSingleDelayError(Functions.identity(), true, prefetch);
+    }
+
     /**
      * Concatenates an {@link Iterable} sequence of {@link SingleSource}s eagerly into a single stream of values.
      * <p>
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatArrayDelayErrorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatArrayDelayErrorTest.java
new file mode 100644
index 0000000000..229d00acc6
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatArrayDelayErrorTest.java
@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.mockito.Mockito.*;
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Action;
+
+public class CompletableConcatArrayDelayErrorTest {
+
+    @Test
+    public void normal() throws Throwable {
+        Action action1 = mock(Action.class);
+        Action action2 = mock(Action.class);
+
+        Completable.concatArrayDelayError(
+                Completable.fromAction(action1),
+                Completable.error(new TestException()),
+                Completable.fromAction(action2)
+        )
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(action1).run();
+
+        verify(action2).run();
+    }
+
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatDelayErrorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatDelayErrorTest.java
new file mode 100644
index 0000000000..fd3124a96c
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableConcatDelayErrorTest.java
@@ -0,0 +1,82 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.mockito.Mockito.*;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.Action;
+
+public class CompletableConcatDelayErrorTest {
+
+    @Test
+    public void normalIterable() throws Throwable {
+        Action action1 = mock(Action.class);
+        Action action2 = mock(Action.class);
+
+        Completable.concatDelayError(Arrays.asList(
+                Completable.fromAction(action1),
+                Completable.error(new TestException()),
+                Completable.fromAction(action2)
+        ))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(action1).run();
+
+        verify(action2).run();
+    }
+
+    @Test
+    public void normalPublisher() throws Throwable {
+        Action action1 = mock(Action.class);
+        Action action2 = mock(Action.class);
+
+        Completable.concatDelayError(Flowable.fromArray(
+                Completable.fromAction(action1),
+                Completable.error(new TestException()),
+                Completable.fromAction(action2)
+        ))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(action1).run();
+
+        verify(action2).run();
+    }
+
+    @Test
+    public void normalPublisherPrefetch() throws Throwable {
+        Action action1 = mock(Action.class);
+        Action action2 = mock(Action.class);
+
+        Completable.concatDelayError(Flowable.fromArray(
+                Completable.fromAction(action1),
+                Completable.error(new TestException()),
+                Completable.fromAction(action2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(action1).run();
+
+        verify(action2).run();
+    }
+
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatArrayEagerDelayErrorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatArrayEagerDelayErrorTest.java
new file mode 100644
index 0000000000..6608fbc424
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatArrayEagerDelayErrorTest.java
@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Maybe;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class MaybeConcatArrayEagerDelayErrorTest {
+
+    @Test
+    public void normal() {
+        Maybe.concatArrayEagerDelayError(
+                Maybe.just(1),
+                Maybe.<Integer>error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        )
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayDelayErrorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayDelayErrorTest.java
new file mode 100644
index 0000000000..10fec20410
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayDelayErrorTest.java
@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class SingleConcatArrayDelayErrorTest {
+
+    @Test
+    public void normal() {
+        Single.concatArrayDelayError(
+                Single.just(1),
+                Single.<Integer>error(new TestException()),
+                Single.just(2)
+        )
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayEagerDelayErrorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayEagerDelayErrorTest.java
new file mode 100644
index 0000000000..ce0df373bb
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatArrayEagerDelayErrorTest.java
@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Single;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class SingleConcatArrayEagerDelayErrorTest {
+
+    @Test
+    public void normal() {
+        Single.concatArrayEagerDelayError(
+                Single.just(1),
+                Single.<Integer>error(new TestException()),
+                Single.just(2)
+        )
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatDelayErrorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatDelayErrorTest.java
new file mode 100644
index 0000000000..83ae9cbf9e
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatDelayErrorTest.java
@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class SingleConcatDelayErrorTest {
+
+    @Test
+    public void normalIterable() {
+        Single.concatDelayError(Arrays.asList(
+                Single.just(1),
+                Single.<Integer>error(new TestException()),
+                Single.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void normalPublisher() {
+        Single.concatDelayError(Flowable.fromArray(
+                Single.just(1),
+                Single.<Integer>error(new TestException()),
+                Single.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void normalPublisherPrefetch() {
+        Single.concatDelayError(Flowable.fromArray(
+                Single.just(1),
+                Single.<Integer>error(new TestException()),
+                Single.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+}
diff --git a/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java b/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java
index 7a0fe1ae7d..94cf62d641 100644
--- a/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java
+++ b/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java
@@ -2388,6 +2388,17 @@ public void concatPublisherDelayError() {
         .assertFailure(TestException.class, 1);
     }
 
+    @Test
+    public void concatPublisherDelayErrorPrefetch() {
+        Maybe.concatDelayError(Flowable.just(Maybe.empty(), Maybe.just(1), Maybe.error(new TestException())), 1)
+        .test()
+        .assertFailure(TestException.class, 1);
+
+        Maybe.concatDelayError(Flowable.just(Maybe.error(new TestException()), Maybe.empty(), Maybe.just(1)), 1)
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
     @Test
     public void concatEagerArray() {
         PublishProcessor<Integer> pp1 = PublishProcessor.create();

From 78c70d6a5365cb8db532d23397d5a0b4c114b72a Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Mon, 27 Jan 2020 12:42:57 +0100
Subject: [PATCH 26/37] 3.x: Add Single.mergeArray & mergeArrayDelayError
 (#6882)

* 3.x: Add Single.mergeArray & mergeArrayDelayError

* Remove unnecessary shortcut
---
 .../java/io/reactivex/rxjava3/core/Maybe.java |  6 +-
 .../io/reactivex/rxjava3/core/Single.java     | 77 ++++++++++++++++++-
 .../CancellableQueueFuseableTest.java         |  4 +-
 .../single/SingleMergeArrayTest.java          | 50 ++++++++++++
 4 files changed, 131 insertions(+), 6 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMergeArrayTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index ce02849d56..5e676681ff 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -1415,7 +1415,7 @@ public static <T> Flowable<T> merge(
     }
 
     /**
-     * Merges an array sequence of {@link MaybeSource} instances into a single {@link Flowable} sequence,
+     * Merges an array of {@link MaybeSource} instances into a single {@link Flowable} sequence,
      * running all {@code MaybeSource}s at once.
      * <p>
      * <img width="640" height="272" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeArray.png" alt="">
@@ -1470,10 +1470,10 @@ public static <T> Flowable<T> mergeArray(MaybeSource<? extends T>... sources) {
      * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeArrayDelayError.png" alt="">
      * <p>
      * This behaves like {@link #merge(Publisher)} except that if any of the merged {@code MaybeSource}s notify of an
-     * error via {@link Subscriber#onError onError}, {@code mergeDelayError} will refrain from propagating that
+     * error via {@link Subscriber#onError onError}, {@code mergeArrayDelayError} will refrain from propagating that
      * error notification until all of the merged {@code MaybeSource}s have finished emitting items.
      * <p>
-     * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeDelayError} will only
+     * Even if multiple merged {@code MaybeSource}s send {@code onError} notifications, {@code mergeArrayDelayError} will only
      * invoke the {@code onError} method of its subscribers once.
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 9f5c3446c5..5e9b084ad2 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -17,7 +17,7 @@
 import java.util.concurrent.*;
 import java.util.stream.*;
 
-import org.reactivestreams.Publisher;
+import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
 import io.reactivex.rxjava3.disposables.Disposable;
@@ -1323,6 +1323,81 @@ public static <T> Flowable<T> merge(
         return merge(Flowable.fromArray(source1, source2, source3, source4));
     }
 
+    /**
+     * Merges an array of {@link SingleSource} instances into a single {@link Flowable} sequence,
+     * running all {@code SingleSource}s at once.
+     * <p>
+     * <img width="640" height="272" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.mergeArray.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code mergeArray} does not operate by default on a particular {@link Scheduler}.</dd>
+     *  <dt><b>Error handling:</b></dt>
+     *  <dd>If any of the source {@code SingleSource}s signal a {@link Throwable} via {@code onError}, the resulting
+     *  {@code Flowable} terminates with that {@code Throwable} and all other source {@code SingleSource}s are disposed.
+     *  If more than one {@code SingleSource} signals an error, the resulting {@code Flowable} may terminate with the
+     *  first one's error or, depending on the concurrency of the sources, may terminate with a
+     *  {@link CompositeException} containing two or more of the various error signals.
+     *  {@code Throwable}s that didn't make into the composite will be sent (individually) to the global error handler via
+     *  {@link RxJavaPlugins#onError(Throwable)} method as {@link UndeliverableException} errors. Similarly, {@code Throwable}s
+     *  signaled by source(s) after the returned {@code Flowable} has been cancelled or terminated with a
+     *  (composite) error will be sent to the same global error handler.
+     *  Use {@link #mergeArrayDelayError(SingleSource...)} to merge sources and terminate only when all source {@code SingleSource}s
+     *  have completed or failed with an error.
+     *  </dd>
+     * </dl>
+     * @param <T> the common and resulting value type
+     * @param sources the array sequence of {@code SingleSource} sources
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @see #mergeArrayDelayError(SingleSource...)
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SafeVarargs
+    public static <T> Flowable<T> mergeArray(SingleSource<? extends T>... sources) {
+        return Flowable.fromArray(sources).flatMapSingle(Functions.identity(), false, sources.length);
+    }
+
+    /**
+     * Flattens an array of {@link SingleSource}s into one {@link Flowable}, in a way that allows a subscriber to receive all
+     * successfully emitted items from each of the source {@code SingleSource}s without being interrupted by an error
+     * notification from one of them.
+     * <p>
+     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.mergeArrayDelayError.png" alt="">
+     * <p>
+     * This behaves like {@link #merge(Publisher)} except that if any of the merged {@code SingleSource}s notify of an
+     * error via {@link Subscriber#onError onError}, {@code mergeArrayDelayError} will refrain from propagating that
+     * error notification until all of the merged {@code SingleSource}s have finished emitting items.
+     * <p>
+     * Even if multiple merged {@code SingleSource}s send {@code onError} notifications, {@code mergeArrayDelayError} will only
+     * invoke the {@code onError} method of its subscribers once.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The operator honors backpressure from downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code mergeArrayDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the common element base type
+     * @param sources
+     *            the array of {@code SingleSource}s
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SafeVarargs
+    @NonNull
+    public static <T> Flowable<T> mergeArrayDelayError(@NonNull SingleSource<? extends T>... sources) {
+        return Flowable.fromArray(sources).flatMapSingle(Functions.identity(), true, sources.length);
+    }
+
     /**
      * Merges an {@link Iterable} sequence of {@link SingleSource} instances into one {@link Flowable} sequence,
      * running all {@code SingleSource}s at once and delaying any error(s) until all sources succeed or fail.
diff --git a/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java b/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java
index ed4718fd1c..e87bfd315a 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/fuseable/CancellableQueueFuseableTest.java
@@ -57,7 +57,7 @@ public void dispose() {
 
     @Test
     public void cancel2() {
-        AbstractEmptyQueueFuseable<Object> qs = new AbstractEmptyQueueFuseable<Object>() {};
+        AbstractEmptyQueueFuseable<Object> qs = new AbstractEmptyQueueFuseable<Object>() { };
 
         assertFalse(qs.isDisposed());
 
@@ -66,7 +66,7 @@ public void cancel2() {
 
     @Test
     public void dispose2() {
-        AbstractEmptyQueueFuseable<Object> qs = new AbstractEmptyQueueFuseable<Object>() {};
+        AbstractEmptyQueueFuseable<Object> qs = new AbstractEmptyQueueFuseable<Object>() { };
 
         assertFalse(qs.isDisposed());
 
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMergeArrayTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMergeArrayTest.java
new file mode 100644
index 0000000000..9434a4fcc1
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleMergeArrayTest.java
@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class SingleMergeArrayTest extends RxJavaTest {
+
+    @Test
+    public void normal() {
+        Single.mergeArray(Single.just(1), Single.just(2), Single.just(3))
+        .test()
+        .assertResult(1, 2, 3);
+    }
+
+    @Test
+    public void error() {
+        Single.mergeArray(Single.just(1), Single.error(new TestException()), Single.just(3))
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void normalDelayError() {
+        Single.mergeArrayDelayError(Single.just(1), Single.just(2), Single.just(3))
+        .test()
+        .assertResult(1, 2, 3);
+    }
+
+    @Test
+    public void errorDelayError() {
+        Single.mergeArrayDelayError(Single.just(1), Single.error(new TestException()), Single.just(3))
+        .test()
+        .assertFailure(TestException.class, 1, 3);
+    }
+}

From c4d995d57dce44c52f2e687689752cacaae8ec8f Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Mon, 27 Jan 2020 15:30:22 +0100
Subject: [PATCH 27/37] 3.x: Add Completable.sequenceEqual (#6884)

---
 .../reactivex/rxjava3/core/Completable.java   | 25 ++++++++++-
 .../CompletableSequenceEqualTest.java         | 43 +++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSequenceEqualTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 253610ef80..e1787b9b46 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -29,7 +29,7 @@
 import io.reactivex.rxjava3.internal.operators.completable.*;
 import io.reactivex.rxjava3.internal.operators.maybe.*;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
-import io.reactivex.rxjava3.internal.operators.single.SingleDelayWithCompletable;
+import io.reactivex.rxjava3.internal.operators.single.*;
 import io.reactivex.rxjava3.observers.TestObserver;
 import io.reactivex.rxjava3.plugins.RxJavaPlugins;
 import io.reactivex.rxjava3.schedulers.Schedulers;
@@ -414,6 +414,29 @@ public static Completable create(@NonNull CompletableOnSubscribe source) {
         return RxJavaPlugins.onAssembly(new CompletableCreate(source));
     }
 
+    /**
+     * Compares two {@link CompletableSource}s and emits {@code true} via a {@link Single} if both complete.
+     * <p>
+     * <img width="640" height="187" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.sequenceEqual.png" alt="">
+     * <dl>
+     * <dt><b>Scheduler:</b></dt>
+     * <dd>{@code sequenceEqual} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param source1 the first {@code CompletableSource} instance
+     * @param source2 the second {@code CompletableSource} instance
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code source1} or {@code source2} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static Single<Boolean> sequenceEqual(@NonNull CompletableSource source1, @NonNull CompletableSource source2) { // NOPMD
+        Objects.requireNonNull(source1, "source1 is null");
+        Objects.requireNonNull(source2, "source2 is null");
+        return mergeArrayDelayError(source1, source2).andThen(Single.just(true));
+    }
+
     /**
      * Constructs a {@code Completable} instance by wrapping the given source callback
      * <strong>without any safeguards; you should manage the lifecycle and response
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSequenceEqualTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSequenceEqualTest.java
new file mode 100644
index 0000000000..b7b68ad321
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSequenceEqualTest.java
@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class CompletableSequenceEqualTest {
+
+    @Test
+    public void bothComplete() {
+        Completable.sequenceEqual(Completable.complete(), Completable.complete())
+        .test()
+        .assertResult(true);
+    }
+
+    @Test
+    public void firstFails() {
+        Completable.sequenceEqual(Completable.error(new TestException()), Completable.complete())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void secondFails() {
+        Completable.sequenceEqual(Completable.complete(), Completable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+    }
+}

From f86753aa4c15717740556ec34418e86edea1b146 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Mon, 27 Jan 2020 15:48:37 +0100
Subject: [PATCH 28/37] 3.x: Add missing startWith overloads (#6885)

* 3.x: Add missing startWith overloads

* Fix Javadocs copy-paste mistakes
---
 .../reactivex/rxjava3/core/Completable.java   |  59 +++++-
 .../io/reactivex/rxjava3/core/Flowable.java   |  75 +++++++
 .../java/io/reactivex/rxjava3/core/Maybe.java | 124 +++++++++++
 .../io/reactivex/rxjava3/core/Observable.java |  66 ++++++
 .../io/reactivex/rxjava3/core/Single.java     | 124 +++++++++++
 .../completable/CompletableStartWithTest.java |  67 ++++++
 .../flowable/FlowableStartWithTest.java       | 153 ++++++++++++++
 .../operators/maybe/MaybeStartWithTest.java   | 197 ++++++++++++++++++
 .../observable/ObservableStartWithTest.java   | 153 ++++++++++++++
 .../operators/single/SingleStartWithTest.java | 126 +++++++++++
 10 files changed, 1141 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableStartWithTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableStartWithTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeStartWithTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableStartWithTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleStartWithTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index e1787b9b46..2ab23028bd 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2595,7 +2595,7 @@ public final Completable retryWhen(@NonNull Function<? super Flowable<Throwable>
 
     /**
      * Returns a {@code Completable} which first runs the other {@link CompletableSource}
-     * then this {@code Completable} if the other completed normally.
+     * then the current {@code Completable} if the other completed normally.
      * <p>
      * <img width="640" height="437" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.startWith.c.png" alt="">
      * <dl>
@@ -2614,9 +2614,61 @@ public final Completable startWith(@NonNull CompletableSource other) {
         return concatArray(other, this);
     }
 
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link SingleSource}
+     * then the current {@code Completable} if the other succeeded normally.
+     * <p>
+     * <img width="640" height="388" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.startWith.s.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the element type of the {@code other} {@code SingleSource}.
+     * @param other the other {@code SingleSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final <T> Flowable<T> startWith(@NonNull SingleSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Single.wrap(other).toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link MaybeSource}
+     * then the current {@code Completable} if the other succeeded or completed normally.
+     * <p>
+     * <img width="640" height="266" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.startWith.m.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the element type of the {@code other} {@code MaybeSource}.
+     * @param other the other {@code MaybeSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final <T> Flowable<T> startWith(@NonNull MaybeSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Maybe.wrap(other).toFlowable(), toFlowable());
+    }
+
     /**
      * Returns an {@link Observable} which first delivers the events
-     * of the other {@link ObservableSource} then runs this {@code Completable}.
+     * of the other {@link ObservableSource} then runs the current {@code Completable}.
      * <p>
      * <img width="640" height="289" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.startWith.o.png" alt="">
      * <dl>
@@ -2635,9 +2687,10 @@ public final <T> Observable<T> startWith(@NonNull ObservableSource<T> other) {
         Objects.requireNonNull(other, "other is null");
         return Observable.wrap(other).concatWith(this.toObservable());
     }
+
     /**
      * Returns a {@link Flowable} which first delivers the events
-     * of the other {@link Publisher} then runs this {@code Completable}.
+     * of the other {@link Publisher} then runs the current {@code Completable}.
      * <p>
      * <img width="640" height="250" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.startWith.p.png" alt="">
      * <dl>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index a994e526c5..453c9e4bba 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -15238,6 +15238,81 @@ public final Flowable<T> startWithIterable(@NonNull Iterable<@NonNull ? extends
         return concatArray(fromIterable(items), this);
     }
 
+    /**
+     * Returns a {@code Flowable} which first runs the other {@link CompletableSource}
+     * then the current {@code Flowable} if the other completed normally.
+     * <p>
+     * <img width="640" height="268" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.startWith.c.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code CompletableSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull CompletableSource other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Completable.wrap(other).<T>toFlowable(), this);
+    }
+
+    /**
+     * Returns a {@code Flowable} which first runs the other {@link SingleSource}
+     * then the current {@code Flowable} if the other succeeded normally.
+     * <p>
+     * <img width="640" height="248" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.startWith.s.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code SingleSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull SingleSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Single.wrap(other).toFlowable(), this);
+    }
+
+    /**
+     * Returns a {@code Flowable} which first runs the other {@link MaybeSource}
+     * then the current {@code Flowable} if the other succeeded or completed normally.
+     * <p>
+     * <img width="640" height="168" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.startWith.m.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code MaybeSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull MaybeSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Maybe.wrap(other).toFlowable(), this);
+    }
+
     /**
      * Returns a {@code Flowable} that emits the items in a specified {@link Publisher} before it begins to emit
      * items emitted by the current {@code Flowable}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 5e676681ff..96ff14c1e9 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -20,6 +20,7 @@
 import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
+import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.exceptions.*;
 import io.reactivex.rxjava3.functions.*;
@@ -4859,6 +4860,129 @@ public final Maybe<T> retryWhen(
         return toFlowable().retryWhen(handler).singleElement();
     }
 
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link CompletableSource}
+     * then the current {@code Maybe} if the other completed normally.
+     * <p>
+     * <img width="640" height="268" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.startWith.c.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code CompletableSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull CompletableSource other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Completable.wrap(other).<T>toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link SingleSource}
+     * then the current {@code Maybe} if the other succeeded normally.
+     * <p>
+     * <img width="640" height="237" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.startWith.s.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code SingleSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull SingleSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Single.wrap(other).toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link MaybeSource}
+     * then the current {@code Maybe} if the other succeeded or completed normally.
+     * <p>
+     * <img width="640" height="178" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.startWith.m.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code MaybeSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull MaybeSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Maybe.wrap(other).toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns an {@link Observable} which first delivers the events
+     * of the other {@link ObservableSource} then runs the current {@code Maybe}.
+     * <p>
+     * <img width="640" height="179" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.startWith.o.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code ObservableSource} to run first
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Observable<T> startWith(@NonNull ObservableSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Observable.wrap(other).concatWith(this.toObservable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first delivers the events
+     * of the other {@link Publisher} then runs the current {@code Maybe}.
+     * <p>
+     * <img width="640" height="179" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.startWith.p.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer
+     *  and expects the other {@code Publisher} to honor it as well.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code Publisher} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Flowable<T> startWith(@NonNull Publisher<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return toFlowable().startWith(other);
+    }
+
     /**
      * Subscribes to a {@code Maybe} and ignores {@code onSuccess} and {@code onComplete} emissions.
      * <p>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index 3ab0be1ab9..6db7ce3cc1 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -12704,6 +12704,72 @@ public final Observable<T> startWithIterable(@NonNull Iterable<@NonNull ? extend
         return concatArray(fromIterable(items), this);
     }
 
+    /**
+     * Returns an {@code Observable} which first runs the other {@link CompletableSource}
+     * then the current {@code Observable} if the other completed normally.
+     * <p>
+     * <img width="640" height="437" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.startWith.c.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code CompletableSource} to run first
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Observable<T> startWith(@NonNull CompletableSource other) {
+        Objects.requireNonNull(other, "other is null");
+        return Observable.concat(Completable.wrap(other).<T>toObservable(), this);
+    }
+
+    /**
+     * Returns an {@code Observable} which first runs the other {@link SingleSource}
+     * then the current {@code Observable} if the other succeeded normally.
+     * <p>
+     * <img width="640" height="248" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.startWith.s.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code SingleSource} to run first
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Observable<T> startWith(@NonNull SingleSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Observable.concat(Single.wrap(other).toObservable(), this);
+    }
+
+    /**
+     * Returns an {@code Observable} which first runs the other {@link MaybeSource}
+     * then the current {@code Observable} if the other succeeded or completed normally.
+     * <p>
+     * <img width="640" height="168" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.startWith.m.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code MaybeSource} to run first
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Observable<T> startWith(@NonNull MaybeSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Observable.concat(Maybe.wrap(other).toObservable(), this);
+    }
+
     /**
      * Returns an {@code Observable} that emits the items in a specified {@link ObservableSource} before it begins to emit
      * items emitted by the current {@code Observable}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 5e9b084ad2..5911000d28 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -20,6 +20,7 @@
 import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
+import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.exceptions.*;
 import io.reactivex.rxjava3.functions.*;
@@ -4286,6 +4287,129 @@ public final Single<T> retryWhen(@NonNull Function<? super Flowable<Throwable>,
         return toSingle(toFlowable().retryWhen(handler));
     }
 
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link CompletableSource}
+     * then the current {@code Single} if the other completed normally.
+     * <p>
+     * <img width="640" height="360" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.startWith.c.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code CompletableSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull CompletableSource other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Completable.wrap(other).<T>toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link SingleSource}
+     * then the current {@code Single} if the other succeeded normally.
+     * <p>
+     * <img width="640" height="341" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.startWith.s.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code SingleSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull SingleSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Single.wrap(other).toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first runs the other {@link MaybeSource}
+     * then the current {@code Single} if the other succeeded or completed normally.
+     * <p>
+     * <img width="640" height="232" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.startWith.m.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code MaybeSource} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @BackpressureSupport(BackpressureKind.FULL)
+    public final Flowable<T> startWith(@NonNull MaybeSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Flowable.concat(Maybe.wrap(other).toFlowable(), toFlowable());
+    }
+
+    /**
+     * Returns an {@link Observable} which first delivers the events
+     * of the other {@link ObservableSource} then runs the current {@code Single}.
+     * <p>
+     * <img width="640" height="175" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.startWith.o.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code ObservableSource} to run first
+     * @return the new {@code Observable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Observable<T> startWith(@NonNull ObservableSource<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return Observable.wrap(other).concatWith(this.toObservable());
+    }
+
+    /**
+     * Returns a {@link Flowable} which first delivers the events
+     * of the other {@link Publisher} then runs the current {@code Single}.
+     * <p>
+     * <img width="640" height="175" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.startWith.p.png" alt="">
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer
+     *  and expects the other {@code Publisher} to honor it as well.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param other the other {@code Publisher} to run first
+     * @return the new {@code Flowable} instance
+     * @throws NullPointerException if {@code other} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Flowable<T> startWith(@NonNull Publisher<T> other) {
+        Objects.requireNonNull(other, "other is null");
+        return toFlowable().startWith(other);
+    }
+
     /**
      * Subscribes to a {@code Single} but ignore its emission or notification.
      * <p>
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableStartWithTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableStartWithTest.java
new file mode 100644
index 0000000000..065a600a0e
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableStartWithTest.java
@@ -0,0 +1,67 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class CompletableStartWithTest {
+
+    @Test
+    public void singleNormal() {
+        Completable.complete().startWith(Single.just(1))
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void singleError() {
+        Runnable run = mock(Runnable.class);
+
+        Completable.fromRunnable(run).startWith(Single.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void maybeNormal() {
+        Completable.complete().startWith(Maybe.just(1))
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void maybeEmptyNormal() {
+        Completable.complete().startWith(Maybe.empty())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void maybeError() {
+        Runnable run = mock(Runnable.class);
+
+        Completable.fromRunnable(run).startWith(Maybe.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableStartWithTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableStartWithTest.java
new file mode 100644
index 0000000000..68f4ee6272
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableStartWithTest.java
@@ -0,0 +1,153 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class FlowableStartWithTest {
+
+    @Test
+    public void justCompletableComplete() {
+        Flowable.just(1).startWith(Completable.complete())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void emptyCompletableComplete() {
+        Flowable.empty().startWith(Completable.complete())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void runCompletableError() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run).startWith(Completable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justSingleJust() {
+        Flowable.just(1).startWith(Single.just(2))
+        .test()
+        .assertResult(2, 1);
+    }
+
+    @Test
+    public void emptySingleJust() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run)
+        .startWith(Single.just(2))
+        .test()
+        .assertResult(2);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void runSingleError() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run).startWith(Single.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justMaybeJust() {
+        Flowable.just(1).startWith(Maybe.just(2))
+        .test()
+        .assertResult(2, 1);
+    }
+
+    @Test
+    public void emptyMaybeJust() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run)
+        .startWith(Maybe.just(2))
+        .test()
+        .assertResult(2);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void runMaybeError() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run).startWith(Maybe.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justFlowableJust() {
+        Flowable.just(1).startWith(Flowable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5, 1);
+    }
+
+    @Test
+    public void emptyFlowableJust() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run)
+        .startWith(Flowable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void emptyFlowableEmpty() {
+        Runnable run = mock(Runnable.class);
+        Runnable run2 = mock(Runnable.class);
+
+        Flowable.fromRunnable(run)
+        .startWith(Flowable.fromRunnable(run2))
+        .test()
+        .assertResult();
+
+        verify(run).run();
+        verify(run2).run();
+    }
+
+    @Test
+    public void runFlowableError() {
+        Runnable run = mock(Runnable.class);
+
+        Flowable.fromRunnable(run).startWith(Flowable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeStartWithTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeStartWithTest.java
new file mode 100644
index 0000000000..87969974d4
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeStartWithTest.java
@@ -0,0 +1,197 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class MaybeStartWithTest {
+
+    @Test
+    public void justCompletableComplete() {
+        Maybe.just(1).startWith(Completable.complete())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void emptyCompletableComplete() {
+        Maybe.empty().startWith(Completable.complete())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void runCompletableError() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run).startWith(Completable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justSingleJust() {
+        Maybe.just(1).startWith(Single.just(2))
+        .test()
+        .assertResult(2, 1);
+    }
+
+    @Test
+    public void emptySingleJust() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run)
+        .startWith(Single.just(2))
+        .test()
+        .assertResult(2);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void runSingleError() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run).startWith(Single.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justMaybeJust() {
+        Maybe.just(1).startWith(Maybe.just(2))
+        .test()
+        .assertResult(2, 1);
+    }
+
+    @Test
+    public void emptyMaybeJust() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run)
+        .startWith(Maybe.just(2))
+        .test()
+        .assertResult(2);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void runMaybeError() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run).startWith(Maybe.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justObservableJust() {
+        Maybe.just(1).startWith(Observable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5, 1);
+    }
+
+    @Test
+    public void emptyObservableJust() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run)
+        .startWith(Observable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void emptyObservableEmpty() {
+        Runnable run = mock(Runnable.class);
+        Runnable run2 = mock(Runnable.class);
+
+        Maybe.fromRunnable(run)
+        .startWith(Observable.fromRunnable(run2))
+        .test()
+        .assertResult();
+
+        verify(run).run();
+        verify(run2).run();
+    }
+
+    @Test
+    public void runObservableError() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run).startWith(Observable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justFlowableJust() {
+        Maybe.just(1).startWith(Flowable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5, 1);
+    }
+
+    @Test
+    public void emptyFlowableJust() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run)
+        .startWith(Flowable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void emptyFlowableEmpty() {
+        Runnable run = mock(Runnable.class);
+        Runnable run2 = mock(Runnable.class);
+
+        Maybe.fromRunnable(run)
+        .startWith(Flowable.fromRunnable(run2))
+        .test()
+        .assertResult();
+
+        verify(run).run();
+        verify(run2).run();
+    }
+
+    @Test
+    public void runFlowableError() {
+        Runnable run = mock(Runnable.class);
+
+        Maybe.fromRunnable(run).startWith(Flowable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableStartWithTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableStartWithTest.java
new file mode 100644
index 0000000000..47cf4dc962
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableStartWithTest.java
@@ -0,0 +1,153 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.observable;
+
+import static org.mockito.Mockito.*;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class ObservableStartWithTest {
+
+    @Test
+    public void justCompletableComplete() {
+        Observable.just(1).startWith(Completable.complete())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void emptyCompletableComplete() {
+        Observable.empty().startWith(Completable.complete())
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void runCompletableError() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run).startWith(Completable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justSingleJust() {
+        Observable.just(1).startWith(Single.just(2))
+        .test()
+        .assertResult(2, 1);
+    }
+
+    @Test
+    public void emptySingleJust() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run)
+        .startWith(Single.just(2))
+        .test()
+        .assertResult(2);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void runSingleError() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run).startWith(Single.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justMaybeJust() {
+        Observable.just(1).startWith(Maybe.just(2))
+        .test()
+        .assertResult(2, 1);
+    }
+
+    @Test
+    public void emptyMaybeJust() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run)
+        .startWith(Maybe.just(2))
+        .test()
+        .assertResult(2);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void runMaybeError() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run).startWith(Maybe.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+
+    @Test
+    public void justObservableJust() {
+        Observable.just(1).startWith(Observable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5, 1);
+    }
+
+    @Test
+    public void emptyObservableJust() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run)
+        .startWith(Observable.just(2, 3, 4, 5))
+        .test()
+        .assertResult(2, 3, 4, 5);
+
+        verify(run).run();
+    }
+
+    @Test
+    public void emptyObservableEmpty() {
+        Runnable run = mock(Runnable.class);
+        Runnable run2 = mock(Runnable.class);
+
+        Observable.fromRunnable(run)
+        .startWith(Observable.fromRunnable(run2))
+        .test()
+        .assertResult();
+
+        verify(run).run();
+        verify(run2).run();
+    }
+
+    @Test
+    public void runObservableError() {
+        Runnable run = mock(Runnable.class);
+
+        Observable.fromRunnable(run).startWith(Observable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+
+        verify(run, never()).run();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleStartWithTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleStartWithTest.java
new file mode 100644
index 0000000000..a3f7e7225a
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleStartWithTest.java
@@ -0,0 +1,126 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class SingleStartWithTest {
+
+    @Test
+    public void justCompletableComplete() {
+        Single.just(1)
+        .startWith(Completable.complete())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void justCompletableError() {
+        Single.just(1)
+        .startWith(Completable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justSingleJust() {
+        Single.just(1)
+        .startWith(Single.just(0))
+        .test()
+        .assertResult(0, 1);
+    }
+
+    @Test
+    public void justSingleError() {
+        Single.just(1)
+        .startWith(Single.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justMaybeJust() {
+        Single.just(1)
+        .startWith(Maybe.just(0))
+        .test()
+        .assertResult(0, 1);
+    }
+
+    @Test
+    public void justMaybeEmpty() {
+        Single.just(1)
+        .startWith(Maybe.empty())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void justMaybeError() {
+        Single.just(1)
+        .startWith(Maybe.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justObservableJust() {
+        Single.just(1)
+        .startWith(Observable.just(-1, 0))
+        .test()
+        .assertResult(-1, 0, 1);
+    }
+
+    @Test
+    public void justObservableEmpty() {
+        Single.just(1)
+        .startWith(Observable.empty())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void justObservableError() {
+        Single.just(1)
+        .startWith(Observable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void justFlowableJust() {
+        Single.just(1)
+        .startWith(Flowable.just(-1, 0))
+        .test()
+        .assertResult(-1, 0, 1);
+    }
+
+    @Test
+    public void justFlowableEmpty() {
+        Single.just(1)
+        .startWith(Observable.empty())
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void justFlowableError() {
+        Single.just(1)
+        .startWith(Flowable.error(new TestException()))
+        .test()
+        .assertFailure(TestException.class);
+    }
+}

From e077ed832678f5efeb15748d2a4aa4aafd29ef5a Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Tue, 28 Jan 2020 10:51:11 +0100
Subject: [PATCH 29/37] 3.x: Add Completable.onErrorReturn[Item] (#6886)

---
 .../reactivex/rxjava3/core/Completable.java   | 58 +++++++++++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  6 +-
 .../completable/CompletableOnErrorReturn.java | 99 +++++++++++++++++++
 .../operators/maybe/MaybeOnErrorReturn.java   | 14 +--
 .../completable/CompletableOnErrorXTest.java  | 57 +++++++++++
 5 files changed, 224 insertions(+), 10 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorReturn.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 2ab23028bd..7e28439ae2 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2323,6 +2323,64 @@ public final Completable onErrorResumeWith(@NonNull CompletableSource fallback)
         return onErrorResumeNext(Functions.justFunction(fallback));
     }
 
+    /**
+     * Ends the flow with a success item returned by a function for the {@link Throwable} error signaled by the current
+     * {@code Completable} instead of signaling the error via {@code onError}.
+     * <p>
+     * <img width="640" height="567" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.onErrorReturn.png" alt="">
+     * <p>
+     * You can use this to prevent errors from propagating or to supply fallback data should errors be
+     * encountered.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorReturn} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the item type to return on error
+     * @param itemSupplier
+     *            a function that returns a single value that will be emitted as success value
+     *            the current {@code Completable} signals an {@code onError} event
+     * @return the new {@link Maybe} instance
+     * @throws NullPointerException if {@code itemSupplier} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <T> Maybe<T> onErrorReturn(@NonNull Function<? super Throwable, ? extends T> itemSupplier) {
+        Objects.requireNonNull(itemSupplier, "itemSupplier is null");
+        return RxJavaPlugins.onAssembly(new CompletableOnErrorReturn<>(this, itemSupplier));
+    }
+
+    /**
+     * Ends the flow with the given success item when the current {@code Completable}
+     * fails instead of signaling the error via {@code onError}.
+     * <p>
+     * <img width="640" height="567" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.onErrorReturnItem.png" alt="">
+     * <p>
+     * You can use this to prevent errors from propagating or to supply fallback data should errors be
+     * encountered.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code onErrorReturnItem} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <T> the item type to return on error
+     * @param item
+     *            the value that is emitted as {@code onSuccess} in case the current {@code Completable} signals an {@code onError}
+     * @return the new {@link Maybe} instance
+     * @throws NullPointerException if {@code item} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <T> Maybe<T> onErrorReturnItem(@NonNull T item) {
+        Objects.requireNonNull(item, "item is null");
+        return onErrorReturn(Functions.justFunction(item));
+    }
+
     /**
      * Nulls out references to the upstream producer and downstream {@link CompletableObserver} if
      * the sequence is terminated or downstream calls {@code dispose()}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 96ff14c1e9..40902efa53 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -4467,7 +4467,7 @@ public final Maybe<T> onErrorResumeNext(@NonNull Function<? super Throwable, ? e
      * Ends the flow with a success item returned by a function for the {@link Throwable} error signaled by the current
      * {@code Maybe} instead of signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onErrorReturn.png" alt="">
+     * <img width="640" height="377" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.onErrorReturn.png" alt="">
      * <p>
      * You can use this to prevent errors from propagating or to supply fallback data should errors be
      * encountered.
@@ -4494,7 +4494,7 @@ public final Maybe<T> onErrorReturn(@NonNull Function<? super Throwable, ? exten
     /**
      * Ends the flow with the given success item when the current {@code Maybe} fails instead of signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onErrorReturn.png" alt="">
+     * <img width="640" height="377" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.onErrorReturnItem.png" alt="">
      * <p>
      * You can use this to prevent errors from propagating or to supply fallback data should errors be
      * encountered.
@@ -4504,7 +4504,7 @@ public final Maybe<T> onErrorReturn(@NonNull Function<? super Throwable, ? exten
      * </dl>
      *
      * @param item
-     *            the value that is emitted as {@code onSuccess} in case this {@code Maybe} signals an {@code onError}
+     *            the value that is emitted as {@code onSuccess} in case the current {@code Maybe} signals an {@code onError}
      * @return the new {@code Maybe} instance
      * @throws NullPointerException if {@code item} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorReturn.java b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorReturn.java
new file mode 100644
index 0000000000..c8fa43499f
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorReturn.java
@@ -0,0 +1,99 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+
+import java.util.Objects;
+
+/**
+ * Returns a value generated via a function if the main source signals an onError.
+ * @param <T> the value type
+ * @since 3.0.0
+ */
+public final class CompletableOnErrorReturn<T> extends Maybe<T> {
+
+    final CompletableSource source;
+
+    final Function<? super Throwable, ? extends T> valueSupplier;
+
+    public CompletableOnErrorReturn(CompletableSource source,
+            Function<? super Throwable, ? extends T> valueSupplier) {
+        this.source = source;
+        this.valueSupplier = valueSupplier;
+    }
+
+    @Override
+    protected void subscribeActual(MaybeObserver<? super T> observer) {
+        source.subscribe(new OnErrorReturnMaybeObserver<>(observer, valueSupplier));
+    }
+
+    static final class OnErrorReturnMaybeObserver<T> implements CompletableObserver, Disposable {
+
+        final MaybeObserver<? super T> downstream;
+
+        final Function<? super Throwable, ? extends T> itemSupplier;
+
+        Disposable upstream;
+
+        OnErrorReturnMaybeObserver(MaybeObserver<? super T> actual,
+                Function<? super Throwable, ? extends T> itemSupplier) {
+            this.downstream = actual;
+            this.itemSupplier = itemSupplier;
+        }
+
+        @Override
+        public void dispose() {
+            upstream.dispose();
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return upstream.isDisposed();
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            T v;
+
+            try {
+                v = Objects.requireNonNull(itemSupplier.apply(e), "The itemSupplier returned a null value");
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                downstream.onError(new CompositeException(e, ex));
+                return;
+            }
+
+            downstream.onSuccess(v);
+        }
+
+        @Override
+        public void onComplete() {
+            downstream.onComplete();
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorReturn.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorReturn.java
index 1a75120e84..190856d5c7 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorReturn.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeOnErrorReturn.java
@@ -27,31 +27,31 @@
  */
 public final class MaybeOnErrorReturn<T> extends AbstractMaybeWithUpstream<T, T> {
 
-    final Function<? super Throwable, ? extends T> valueSupplier;
+    final Function<? super Throwable, ? extends T> itemSupplier;
 
     public MaybeOnErrorReturn(MaybeSource<T> source,
-            Function<? super Throwable, ? extends T> valueSupplier) {
+            Function<? super Throwable, ? extends T> itemSupplier) {
         super(source);
-        this.valueSupplier = valueSupplier;
+        this.itemSupplier = itemSupplier;
     }
 
     @Override
     protected void subscribeActual(MaybeObserver<? super T> observer) {
-        source.subscribe(new OnErrorReturnMaybeObserver<>(observer, valueSupplier));
+        source.subscribe(new OnErrorReturnMaybeObserver<>(observer, itemSupplier));
     }
 
     static final class OnErrorReturnMaybeObserver<T> implements MaybeObserver<T>, Disposable {
 
         final MaybeObserver<? super T> downstream;
 
-        final Function<? super Throwable, ? extends T> valueSupplier;
+        final Function<? super Throwable, ? extends T> itemSupplier;
 
         Disposable upstream;
 
         OnErrorReturnMaybeObserver(MaybeObserver<? super T> actual,
                 Function<? super Throwable, ? extends T> valueSupplier) {
             this.downstream = actual;
-            this.valueSupplier = valueSupplier;
+            this.itemSupplier = valueSupplier;
         }
 
         @Override
@@ -83,7 +83,7 @@ public void onError(Throwable e) {
             T v;
 
             try {
-                v = Objects.requireNonNull(valueSupplier.apply(e), "The valueSupplier returned a null value");
+                v = Objects.requireNonNull(itemSupplier.apply(e), "The itemSupplier returned a null value");
             } catch (Throwable ex) {
                 Exceptions.throwIfFatal(ex);
                 downstream.onError(new CompositeException(e, ex));
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorXTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorXTest.java
index 4a1333b530..531f13b8cc 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorXTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableOnErrorXTest.java
@@ -15,10 +15,16 @@
 
 import static org.junit.Assert.assertEquals;
 
+import java.io.IOException;
+
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.functions.Functions;
+import io.reactivex.rxjava3.subjects.CompletableSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
 
 public class CompletableOnErrorXTest extends RxJavaTest {
 
@@ -46,4 +52,55 @@ public CompletableSource apply(Throwable e) throws Exception {
 
         assertEquals(0, call[0]);
     }
+
+    @Test
+    public void onErrorReturnConst() {
+        Completable.error(new TestException())
+        .onErrorReturnItem(1)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void onErrorReturn() {
+        Completable.error(new TestException())
+        .onErrorReturn(Functions.justFunction(1))
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void onErrorReturnFunctionThrows() {
+        TestHelper.assertCompositeExceptions(Completable.error(new TestException())
+        .onErrorReturn(new Function<Throwable, Object>() {
+            @Override
+            public Object apply(Throwable v) throws Exception {
+                throw new IOException();
+            }
+        })
+        .to(TestHelper.testConsumer()), TestException.class, IOException.class);
+    }
+
+    @Test
+    public void onErrorReturnEmpty() {
+        Completable.complete()
+        .onErrorReturnItem(2)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void onErrorReturnDispose() {
+        TestHelper.checkDisposed(CompletableSubject.create().onErrorReturnItem(1));
+    }
+
+    @Test
+    public void onErrorReturnDoubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeCompletableToMaybe(new Function<Completable, MaybeSource<Object>>() {
+            @Override
+            public MaybeSource<Object> apply(Completable v) throws Exception {
+                return v.onErrorReturnItem(1);
+            }
+        });
+    }
 }

From 2d8660e070fe65b8089855ba1a58ef49d7c1b70a Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Tue, 28 Jan 2020 12:06:37 +0100
Subject: [PATCH 30/37] 3.x: Add safeSubscribe to Maybe, Single & Completable
 (#6887)

---
 docs/Operator-Matrix.md                       |  27 +--
 .../reactivex/rxjava3/core/Completable.java   |  25 +++
 .../java/io/reactivex/rxjava3/core/Maybe.java |  25 +++
 .../io/reactivex/rxjava3/core/Single.java     |  25 +++
 .../observers/SafeCompletableObserver.java    |  78 +++++++
 .../internal/observers/SafeMaybeObserver.java |  91 ++++++++
 .../observers/SafeSingleObserver.java         |  79 +++++++
 .../CompletableSafeSubscribeTest.java         | 148 +++++++++++++
 .../maybe/MaybeSafeSubscribeTest.java         | 197 ++++++++++++++++++
 .../single/SingleSafeSubscribeTest.java       | 154 ++++++++++++++
 .../util/OperatorMatrixGenerator.java         |   7 +-
 11 files changed, 837 insertions(+), 19 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/observers/SafeCompletableObserver.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/observers/SafeMaybeObserver.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/observers/SafeSingleObserver.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSafeSubscribeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSafeSubscribeTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSafeSubscribeTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index 2ddd1cf21f..dfa16162e7 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -138,8 +138,8 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='mapOptional'></a>`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
 <a name='materialize'></a>`materialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='merge'></a>`merge`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='mergeArray'></a>`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='mergeArrayDelayError'></a>`mergeArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeArray'></a>`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='mergeArrayDelayError'></a>`mergeArrayDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='mergeDelayError'></a>`mergeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='mergeWith'></a>`mergeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='never'></a>`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -151,8 +151,8 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='onErrorComplete'></a>`onErrorComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeNext'></a>`onErrorResumeNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeWith'></a>`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='onErrorReturn'></a>`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
-<a name='onErrorReturnItem'></a>`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='onErrorReturn'></a>`onErrorReturn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='onErrorReturnItem'></a>`onErrorReturnItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onTerminateDetach'></a>`onTerminateDetach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='parallel'></a>`parallel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Needs backpressure thus not supported outside Flowable.'>([86](#notes-86))</sup>|
 <a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
@@ -168,11 +168,11 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='retry'></a>`retry`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='retryWhen'></a>`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
 <a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
-<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|
+<a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|
 <a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
 <a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
@@ -185,7 +185,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|
 <a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|
-<a name='startWith'></a>`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_half.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='startWith'></a>`startWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='startWithArray'></a>`startWithArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([96](#notes-96))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([96](#notes-96))</sup>|
 <a name='startWithItem'></a>`startWithItem`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([97](#notes-97))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of another reactive type.'>([97](#notes-97))</sup>|
 <a name='startWithIterable'></a>`startWithIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([98](#notes-98))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use startWith() of Flowable or Observable.'>([98](#notes-98))</sup>|
@@ -237,7 +237,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([111](#notes-111))</sup>|
 <a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([112](#notes-112))</sup>|
 <a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([113](#notes-113))</sup>|
-<a name='total'></a>**237 operators** | **215** | **209** | **116** | **103** | **80** |
+<a name='total'></a>**237 operators** | **215** | **209** | **118** | **107** | **84** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -356,13 +356,4 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 
 #### Under development
 
-1. Single.mergeArray()
-2. Single.mergeArrayDelayError()
-3. Completable.onErrorReturn()
-4. Completable.onErrorReturnItem()
-5. Maybe.safeSubscribe()
-6. Single.safeSubscribe()
-7. Completable.safeSubscribe()
-8. Completable.sequenceEqual()
-9. Maybe.startWith()
-10. Single.startWith()
+*Currently, all intended operators are implemented.*
diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 7e28439ae2..83e7848a51 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -2651,6 +2651,31 @@ public final Completable retryWhen(@NonNull Function<? super Flowable<Throwable>
         return fromPublisher(toFlowable().retryWhen(handler));
     }
 
+    /**
+     * Wraps the given {@link CompletableObserver}, catches any {@link RuntimeException}s thrown by its
+     * {@link CompletableObserver#onSubscribe(Disposable)}, {@link CompletableObserver#onError(Throwable)}
+     * or {@link CompletableObserver#onComplete()} methods and routes those to the global
+     * error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     * <p>
+     * By default, the {@code Completable} protocol forbids the {@code onXXX} methods to throw, but some
+     * {@code CompletableObserver} implementation may do it anyway, causing undefined behavior in the
+     * upstream. This method and the underlying safe wrapper ensures such misbehaving consumers don't
+     * disrupt the protocol.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code safeSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param observer the potentially misbehaving {@code CompletableObserver}
+     * @throws NullPointerException if {@code observer} is {@code null}
+     * @see #subscribe(Action, Consumer)
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void safeSubscribe(@NonNull CompletableObserver observer) {
+        Objects.requireNonNull(observer, "observer is null");
+        subscribe(new SafeCompletableObserver(observer));
+    }
+
     /**
      * Returns a {@code Completable} which first runs the other {@link CompletableSource}
      * then the current {@code Completable} if the other completed normally.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 40902efa53..ba42452513 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -4860,6 +4860,31 @@ public final Maybe<T> retryWhen(
         return toFlowable().retryWhen(handler).singleElement();
     }
 
+    /**
+     * Wraps the given {@link MaybeObserver}, catches any {@link RuntimeException}s thrown by its
+     * {@link MaybeObserver#onSubscribe(Disposable)}, {@link MaybeObserver#onSuccess(Object)},
+     * {@link MaybeObserver#onError(Throwable)} or {@link MaybeObserver#onComplete()} methods
+     * and routes those to the global error handler via {@link RxJavaPlugins#onError(Throwable)}.
+     * <p>
+     * By default, the {@code Maybe} protocol forbids the {@code onXXX} methods to throw, but some
+     * {@code MaybeObserver} implementation may do it anyway, causing undefined behavior in the
+     * upstream. This method and the underlying safe wrapper ensures such misbehaving consumers don't
+     * disrupt the protocol.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code safeSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param observer the potentially misbehaving {@code MaybeObserver}
+     * @throws NullPointerException if {@code observer} is {@code null}
+     * @see #subscribe(Consumer,Consumer, Action)
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void safeSubscribe(@NonNull MaybeObserver<? super T> observer) {
+        Objects.requireNonNull(observer, "observer is null");
+        subscribe(new SafeMaybeObserver<>(observer));
+    }
+
     /**
      * Returns a {@link Flowable} which first runs the other {@link CompletableSource}
      * then the current {@code Maybe} if the other completed normally.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 5911000d28..12431fedb6 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -4287,6 +4287,31 @@ public final Single<T> retryWhen(@NonNull Function<? super Flowable<Throwable>,
         return toSingle(toFlowable().retryWhen(handler));
     }
 
+    /**
+     * Wraps the given {@link SingleObserver}, catches any {@link RuntimeException}s thrown by its
+     * {@link SingleObserver#onSubscribe(Disposable)}, {@link SingleObserver#onSuccess(Object)} or
+     * {@link SingleObserver#onError(Throwable)} methods* and routes those to the global error handler
+     * via {@link RxJavaPlugins#onError(Throwable)}.
+     * <p>
+     * By default, the {@code Single} protocol forbids the {@code onXXX} methods to throw, but some
+     * {@code SingleObserver} implementation may do it anyway, causing undefined behavior in the
+     * upstream. This method and the underlying safe wrapper ensures such misbehaving consumers don't
+     * disrupt the protocol.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code safeSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param observer the potentially misbehaving {@code SingleObserver}
+     * @throws NullPointerException if {@code observer} is {@code null}
+     * @see #subscribe(Consumer,Consumer)
+     * @since 3.0.0
+     */
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final void safeSubscribe(@NonNull SingleObserver<? super T> observer) {
+        Objects.requireNonNull(observer, "observer is null");
+        subscribe(new SafeSingleObserver<>(observer));
+    }
+
     /**
      * Returns a {@link Flowable} which first runs the other {@link CompletableSource}
      * then the current {@code Single} if the other completed normally.
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/SafeCompletableObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/SafeCompletableObserver.java
new file mode 100644
index 0000000000..d9e929c234
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/observers/SafeCompletableObserver.java
@@ -0,0 +1,78 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.observers;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.CompletableObserver;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Wraps another {@link CompletableObserver} and catches exceptions thrown by its
+ * {@code onSubscribe}, {@code onError} or
+ * {@code onComplete} methods despite the protocol forbids it.
+ * <p>
+ * Such exceptions are routed to the {@link RxJavaPlugins#onError(Throwable)} handler.
+ *
+ * @since 3.0.0
+ */
+public final class SafeCompletableObserver implements CompletableObserver {
+
+    final CompletableObserver downstream;
+
+    boolean onSubscribeFailed;
+
+    public SafeCompletableObserver(CompletableObserver downstream) {
+        this.downstream = downstream;
+    }
+
+    @Override
+    public void onSubscribe(@NonNull Disposable d) {
+        try {
+            downstream.onSubscribe(d);
+        } catch (Throwable ex) {
+            Exceptions.throwIfFatal(ex);
+            onSubscribeFailed = true;
+            d.dispose();
+            RxJavaPlugins.onError(ex);
+        }
+    }
+
+    @Override
+    public void onError(@NonNull Throwable e) {
+        if (onSubscribeFailed) {
+            RxJavaPlugins.onError(e);
+        } else {
+            try {
+                downstream.onError(e);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(new CompositeException(e, ex));
+            }
+        }
+    }
+
+    @Override
+    public void onComplete() {
+        if (!onSubscribeFailed) {
+            try {
+                downstream.onComplete();
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(ex);
+            }
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/SafeMaybeObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/SafeMaybeObserver.java
new file mode 100644
index 0000000000..a6e794b1fd
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/observers/SafeMaybeObserver.java
@@ -0,0 +1,91 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.observers;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.MaybeObserver;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Wraps another {@link MaybeObserver} and catches exceptions thrown by its
+ * {@code onSubscribe}, {@code onSuccess}, {@code onError} or
+ * {@code onComplete} methods despite the protocol forbids it.
+ * <p>
+ * Such exceptions are routed to the {@link RxJavaPlugins#onError(Throwable)} handler.
+ *
+ * @param <T> the element type of the sequence
+ * @since 3.0.0
+ */
+public final class SafeMaybeObserver<T> implements MaybeObserver<T> {
+
+    final MaybeObserver<? super T> downstream;
+
+    boolean onSubscribeFailed;
+
+    public SafeMaybeObserver(MaybeObserver<? super T> downstream) {
+        this.downstream = downstream;
+    }
+
+    @Override
+    public void onSubscribe(@NonNull Disposable d) {
+        try {
+            downstream.onSubscribe(d);
+        } catch (Throwable ex) {
+            Exceptions.throwIfFatal(ex);
+            onSubscribeFailed = true;
+            d.dispose();
+            RxJavaPlugins.onError(ex);
+        }
+    }
+
+    @Override
+    public void onSuccess(@NonNull T t) {
+        if (!onSubscribeFailed) {
+            try {
+                downstream.onSuccess(t);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(ex);
+            }
+        }
+    }
+
+    @Override
+    public void onError(@NonNull Throwable e) {
+        if (onSubscribeFailed) {
+            RxJavaPlugins.onError(e);
+        } else {
+            try {
+                downstream.onError(e);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(new CompositeException(e, ex));
+            }
+        }
+    }
+
+    @Override
+    public void onComplete() {
+        if (!onSubscribeFailed) {
+            try {
+                downstream.onComplete();
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(ex);
+            }
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/observers/SafeSingleObserver.java b/src/main/java/io/reactivex/rxjava3/internal/observers/SafeSingleObserver.java
new file mode 100644
index 0000000000..6757350756
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/observers/SafeSingleObserver.java
@@ -0,0 +1,79 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.observers;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.SingleObserver;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * Wraps another {@link SingleObserver} and catches exceptions thrown by its
+ * {@code onSubscribe}, {@code onSuccess} or {@code onError} methods despite
+ * the protocol forbids it.
+ * <p>
+ * Such exceptions are routed to the {@link RxJavaPlugins#onError(Throwable)} handler.
+ *
+ * @param <T> the element type of the sequence
+ * @since 3.0.0
+ */
+public final class SafeSingleObserver<T> implements SingleObserver<T> {
+
+    final SingleObserver<? super T> downstream;
+
+    boolean onSubscribeFailed;
+
+    public SafeSingleObserver(SingleObserver<? super T> downstream) {
+        this.downstream = downstream;
+    }
+
+    @Override
+    public void onSubscribe(@NonNull Disposable d) {
+        try {
+            downstream.onSubscribe(d);
+        } catch (Throwable ex) {
+            Exceptions.throwIfFatal(ex);
+            onSubscribeFailed = true;
+            d.dispose();
+            RxJavaPlugins.onError(ex);
+        }
+    }
+
+    @Override
+    public void onSuccess(@NonNull T t) {
+        if (!onSubscribeFailed) {
+            try {
+                downstream.onSuccess(t);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(ex);
+            }
+        }
+    }
+
+    @Override
+    public void onError(@NonNull Throwable e) {
+        if (onSubscribeFailed) {
+            RxJavaPlugins.onError(e);
+        } else {
+            try {
+                downstream.onError(e);
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                RxJavaPlugins.onError(new CompositeException(e, ex));
+            }
+        }
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSafeSubscribeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSafeSubscribeTest.java
new file mode 100644
index 0000000000..234fb0290c
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/completable/CompletableSafeSubscribeTest.java
@@ -0,0 +1,148 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.completable;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class CompletableSafeSubscribeTest {
+
+    @Test
+    public void normalError() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            CompletableObserver consumer = mock(CompletableObserver.class);
+
+            Completable.error(new TestException())
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onError(any(TestException.class));
+            order.verifyNoMoreInteractions();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void normalEmpty() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            CompletableObserver consumer = mock(CompletableObserver.class);
+
+            Completable.complete()
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onComplete();
+            order.verifyNoMoreInteractions();
+        });
+    }
+
+    @Test
+    public void onSubscribeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            CompletableObserver consumer = mock(CompletableObserver.class);
+            doThrow(new TestException()).when(consumer).onSubscribe(any());
+
+            Disposable d = Disposable.empty();
+
+            new Completable() {
+                @Override
+                protected void subscribeActual(@NonNull CompletableObserver observer) {
+                    observer.onSubscribe(d);
+                    // none of the following should arrive at the consumer
+                    observer.onError(new IOException());
+                    observer.onComplete();
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verifyNoMoreInteractions();
+
+            assertTrue(d.isDisposed());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+            TestHelper.assertUndeliverable(errors, 1, IOException.class);
+        });
+    }
+
+    @Test
+    public void onErrorCrash() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            CompletableObserver consumer = mock(CompletableObserver.class);
+            doThrow(new TestException()).when(consumer).onError(any());
+
+            new Completable() {
+                @Override
+                protected void subscribeActual(@NonNull CompletableObserver observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    // none of the following should arrive at the consumer
+                    observer.onError(new IOException());
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onError(any(IOException.class));
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertError(errors, 0, CompositeException.class);
+
+            CompositeException compositeException = (CompositeException)errors.get(0);
+            TestHelper.assertError(compositeException.getExceptions(), 0, IOException.class);
+            TestHelper.assertError(compositeException.getExceptions(), 1, TestException.class);
+        });
+    }
+
+    @Test
+    public void onCompleteCrash() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            CompletableObserver consumer = mock(CompletableObserver.class);
+            doThrow(new TestException()).when(consumer).onComplete();
+
+            new Completable() {
+                @Override
+                protected void subscribeActual(@NonNull CompletableObserver observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    // none of the following should arrive at the consumer
+                    observer.onComplete();
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onComplete();
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSafeSubscribeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSafeSubscribeTest.java
new file mode 100644
index 0000000000..5083c20f2c
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeSafeSubscribeTest.java
@@ -0,0 +1,197 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class MaybeSafeSubscribeTest {
+
+    @Test
+    public void normalSuccess() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+
+            Maybe.just(1)
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onSuccess(1);
+            order.verifyNoMoreInteractions();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void normalError() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+
+            Maybe.<Integer>error(new TestException())
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onError(any(TestException.class));
+            order.verifyNoMoreInteractions();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void normalEmpty() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+
+            Maybe.<Integer>empty()
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onComplete();
+            order.verifyNoMoreInteractions();
+        });
+    }
+
+    @Test
+    public void onSubscribeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+            doThrow(new TestException()).when(consumer).onSubscribe(any());
+
+            Disposable d = Disposable.empty();
+
+            new Maybe<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull MaybeObserver<? super Integer> observer) {
+                    observer.onSubscribe(d);
+                    // none of the following should arrive at the consumer
+                    observer.onSuccess(1);
+                    observer.onError(new IOException());
+                    observer.onComplete();
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verifyNoMoreInteractions();
+
+            assertTrue(d.isDisposed());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+            TestHelper.assertUndeliverable(errors, 1, IOException.class);
+        });
+    }
+
+    @Test
+    public void onSuccessCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+            doThrow(new TestException()).when(consumer).onSuccess(any());
+
+            new Maybe<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull MaybeObserver<? super Integer> observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    observer.onSuccess(1);
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onSuccess(1);
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void onErrorCrash() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+            doThrow(new TestException()).when(consumer).onError(any());
+
+            new Maybe<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull MaybeObserver<? super Integer> observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    // none of the following should arrive at the consumer
+                    observer.onError(new IOException());
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onError(any(IOException.class));
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertError(errors, 0, CompositeException.class);
+
+            CompositeException compositeException = (CompositeException)errors.get(0);
+            TestHelper.assertError(compositeException.getExceptions(), 0, IOException.class);
+            TestHelper.assertError(compositeException.getExceptions(), 1, TestException.class);
+        });
+    }
+
+    @Test
+    public void onCompleteCrash() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            MaybeObserver<Integer> consumer = mock(MaybeObserver.class);
+            doThrow(new TestException()).when(consumer).onComplete();
+
+            new Maybe<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull MaybeObserver<? super Integer> observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    // none of the following should arrive at the consumer
+                    observer.onComplete();
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onComplete();
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSafeSubscribeTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSafeSubscribeTest.java
new file mode 100644
index 0000000000..80abb4cb1a
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleSafeSubscribeTest.java
@@ -0,0 +1,154 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleSafeSubscribeTest {
+
+    @Test
+    public void normalSuccess() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            SingleObserver<Integer> consumer = mock(SingleObserver.class);
+
+            Single.just(1)
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onSuccess(1);
+            order.verifyNoMoreInteractions();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void normalError() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            SingleObserver<Integer> consumer = mock(SingleObserver.class);
+
+            Single.<Integer>error(new TestException())
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onError(any(TestException.class));
+            order.verifyNoMoreInteractions();
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void onSubscribeCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            SingleObserver<Integer> consumer = mock(SingleObserver.class);
+            doThrow(new TestException()).when(consumer).onSubscribe(any());
+
+            Disposable d = Disposable.empty();
+
+            new Single<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull SingleObserver<? super Integer> observer) {
+                    observer.onSubscribe(d);
+                    // none of the following should arrive at the consumer
+                    observer.onSuccess(1);
+                    observer.onError(new IOException());
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verifyNoMoreInteractions();
+
+            assertTrue(d.isDisposed());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+            TestHelper.assertUndeliverable(errors, 1, IOException.class);
+        });
+    }
+
+    @Test
+    public void onSuccessCrash() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            SingleObserver<Integer> consumer = mock(SingleObserver.class);
+            doThrow(new TestException()).when(consumer).onSuccess(any());
+
+            new Single<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull SingleObserver<? super Integer> observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    observer.onSuccess(1);
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onSuccess(1);
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void onErrorCrash() throws Throwable  {
+        TestHelper.withErrorTracking(errors -> {
+            @SuppressWarnings("unchecked")
+            SingleObserver<Integer> consumer = mock(SingleObserver.class);
+            doThrow(new TestException()).when(consumer).onError(any());
+
+            new Single<Integer>() {
+                @Override
+                protected void subscribeActual(@NonNull SingleObserver<? super Integer> observer) {
+                    observer.onSubscribe(Disposable.empty());
+                    // none of the following should arrive at the consumer
+                    observer.onError(new IOException());
+                }
+            }
+            .safeSubscribe(consumer);
+
+            InOrder order = inOrder(consumer);
+            order.verify(consumer).onSubscribe(any(Disposable.class));
+            order.verify(consumer).onError(any(IOException.class));
+            order.verifyNoMoreInteractions();
+
+            TestHelper.assertError(errors, 0, CompositeException.class);
+
+            CompositeException compositeException = (CompositeException)errors.get(0);
+            TestHelper.assertError(compositeException.getExceptions(), 0, IOException.class);
+            TestHelper.assertError(compositeException.getExceptions(), 1, TestException.class);
+        });
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
index 0e2c0ada16..714a6809f9 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/OperatorMatrixGenerator.java
@@ -147,7 +147,12 @@ public static void main(String[] args) throws IOException {
                     out.println("<br/>");
                 }
             }
-            if (!tbdList.isEmpty()) {
+            if (tbdList.isEmpty()) {
+                out.println();
+                out.println("#### Under development");
+                out.println();
+                out.println("*Currently, all intended operators are implemented.*");
+            } else {
                 out.println();
                 out.println("#### Under development");
                 out.println();

From 1ede60786a1a8f00f1fb3968d0701a323ed86f2f Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Tue, 28 Jan 2020 15:59:54 +0100
Subject: [PATCH 31/37] 3.x: Use more appropriate operators when delegating to
 Flowable ops (#6888)

* 3.x: Use more appropriate operators when delegating to Flowable ops

* Remove now-unused classes
---
 .../java/io/reactivex/rxjava3/core/Maybe.java | 20 ++-----
 .../io/reactivex/rxjava3/core/Single.java     | 47 +++++++---------
 ...ava => FlowableFlatMapMaybePublisher.java} | 32 ++++++-----
 .../FlowableFlatMapSinglePublisher.java       | 49 +++++++++++++++++
 .../FlowableConcatMapMaybePublisher.java}     | 38 +++++++------
 .../FlowableConcatMapSinglePublisher.java     | 55 +++++++++++++++++++
 .../mixed/ObservableConcatMapSingle.java      |  4 +-
 .../single/SingleInternalHelper.java          | 16 ------
 .../single/SingleInternalHelperTest.java      |  6 --
 .../io/reactivex/rxjava3/maybe/MaybeTest.java |  2 -
 10 files changed, 173 insertions(+), 96 deletions(-)
 rename src/main/java/io/reactivex/rxjava3/internal/operators/flowable/{FlowableFlatMapPublisher.java => FlowableFlatMapMaybePublisher.java} (53%)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapSinglePublisher.java
 rename src/main/java/io/reactivex/rxjava3/internal/operators/{flowable/FlowableConcatMapPublisher.java => mixed/FlowableConcatMapMaybePublisher.java} (51%)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapSinglePublisher.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index ba42452513..d4116406b4 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -344,11 +344,10 @@ public static <T> Flowable<T> concat(@NonNull Publisher<@NonNull ? extends Maybe
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <T> Flowable<T> concat(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources, int prefetch) {
         Objects.requireNonNull(sources, "sources is null");
         ObjectHelper.verifyPositive(prefetch, "prefetch");
-        return RxJavaPlugins.onAssembly(new FlowableConcatMapPublisher(sources, MaybeToPublisher.instance(), prefetch, ErrorMode.IMMEDIATE));
+        return RxJavaPlugins.onAssembly(new FlowableConcatMapMaybePublisher<>(sources, Functions.identity(), ErrorMode.IMMEDIATE, prefetch));
     }
 
     /**
@@ -1141,7 +1140,7 @@ public static <T> Maybe<T> fromRunnable(@NonNull Runnable run) {
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public static <T> Flowable<T> merge(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources) {
-        return merge(Flowable.fromIterable(sources));
+        return Flowable.fromIterable(sources).flatMapMaybe(Functions.identity(), false, Integer.MAX_VALUE);
     }
 
     /**
@@ -1218,11 +1217,10 @@ public static <T> Flowable<T> merge(@NonNull Publisher<@NonNull ? extends MaybeS
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <T> Flowable<T> merge(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
         Objects.requireNonNull(sources, "sources is null");
         ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
-        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, MaybeToPublisher.instance(), false, maxConcurrency, 1));
+        return RxJavaPlugins.onAssembly(new FlowableFlatMapMaybePublisher<>(sources, Functions.identity(), false, maxConcurrency));
     }
 
     /**
@@ -1490,7 +1488,6 @@ public static <T> Flowable<T> mergeArray(MaybeSource<? extends T>... sources) {
      * @throws NullPointerException if {@code sources} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
@@ -1498,10 +1495,7 @@ public static <T> Flowable<T> mergeArray(MaybeSource<? extends T>... sources) {
     @NonNull
     public static <T> Flowable<T> mergeArrayDelayError(@NonNull MaybeSource<? extends T>... sources) {
         Objects.requireNonNull(sources, "sources is null");
-        if (sources.length == 0) {
-            return Flowable.empty();
-        }
-        return Flowable.fromArray(sources).flatMap((Function)MaybeToPublisher.instance(), true, sources.length);
+        return Flowable.fromArray(sources).flatMapMaybe(Functions.identity(), true, Math.max(1, sources.length));
     }
 
     /**
@@ -1533,13 +1527,12 @@ public static <T> Flowable<T> mergeArrayDelayError(@NonNull MaybeSource<? extend
      * @throws NullPointerException if {@code sources} is {@code null}
      * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public static <T> Flowable<T> mergeDelayError(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources) {
-        return Flowable.fromIterable(sources).flatMap((Function)MaybeToPublisher.instance(), true);
+        return Flowable.fromIterable(sources).flatMapMaybe(Functions.identity(), true, Integer.MAX_VALUE);
     }
 
     /**
@@ -1609,7 +1602,6 @@ public static <T> Flowable<T> mergeDelayError(@NonNull Publisher<@NonNull ? exte
      * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
      * @since 2.2
      */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     @BackpressureSupport(BackpressureKind.FULL)
     @CheckReturnValue
     @NonNull
@@ -1617,7 +1609,7 @@ public static <T> Flowable<T> mergeDelayError(@NonNull Publisher<@NonNull ? exte
     public static <T> Flowable<T> mergeDelayError(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
         Objects.requireNonNull(sources, "sources is null");
         ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
-        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, MaybeToPublisher.instance(), true, maxConcurrency, 1));
+        return RxJavaPlugins.onAssembly(new FlowableFlatMapMaybePublisher<>(sources, Functions.identity(), true, maxConcurrency));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 12431fedb6..7db69e5bc5 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -20,7 +20,6 @@
 import org.reactivestreams.*;
 
 import io.reactivex.rxjava3.annotations.*;
-import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.exceptions.*;
 import io.reactivex.rxjava3.functions.*;
@@ -32,7 +31,7 @@
 import io.reactivex.rxjava3.internal.operators.flowable.*;
 import io.reactivex.rxjava3.internal.operators.maybe.*;
 import io.reactivex.rxjava3.internal.operators.mixed.*;
-import io.reactivex.rxjava3.internal.operators.observable.*;
+import io.reactivex.rxjava3.internal.operators.observable.ObservableSingleSingle;
 import io.reactivex.rxjava3.internal.operators.single.*;
 import io.reactivex.rxjava3.internal.util.ErrorMode;
 import io.reactivex.rxjava3.observers.TestObserver;
@@ -195,7 +194,7 @@ public static <T> Single<T> ambArray(@NonNull SingleSource<? extends T>... sourc
     @SchedulerSupport(SchedulerSupport.NONE)
     @BackpressureSupport(BackpressureKind.FULL)
     public static <T> Flowable<T> concat(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources) {
-        return concat(Flowable.fromIterable(sources));
+        return Flowable.fromIterable(sources).concatMapSingleDelayError(Functions.identity(), false);
     }
 
     /**
@@ -216,10 +215,9 @@ public static <T> Flowable<T> concat(@NonNull Iterable<@NonNull ? extends Single
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <T> Observable<T> concat(@NonNull ObservableSource<? extends SingleSource<? extends T>> sources) {
         Objects.requireNonNull(sources, "sources is null");
-        return RxJavaPlugins.onAssembly(new ObservableConcatMap(sources, SingleInternalHelper.toObservable(), 2, ErrorMode.IMMEDIATE));
+        return RxJavaPlugins.onAssembly(new ObservableConcatMapSingle<>(sources, Functions.identity(), ErrorMode.IMMEDIATE, 2));
     }
 
     /**
@@ -272,11 +270,10 @@ public static <T> Flowable<T> concat(@NonNull Publisher<@NonNull ? extends Singl
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <T> Flowable<T> concat(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources, int prefetch) {
         Objects.requireNonNull(sources, "sources is null");
         ObjectHelper.verifyPositive(prefetch, "prefetch");
-        return RxJavaPlugins.onAssembly(new FlowableConcatMapPublisher(sources, SingleInternalHelper.toFlowable(), prefetch, ErrorMode.IMMEDIATE));
+        return RxJavaPlugins.onAssembly(new FlowableConcatMapSinglePublisher<>(sources, Functions.identity(), ErrorMode.IMMEDIATE, prefetch));
     }
 
     /**
@@ -308,7 +305,7 @@ public static <T> Flowable<T> concat(
      ) {
         Objects.requireNonNull(source1, "source1 is null");
         Objects.requireNonNull(source2, "source2 is null");
-        return concat(Flowable.fromArray(source1, source2));
+        return Flowable.fromArray(source1, source2).concatMapSingleDelayError(Functions.identity(), false);
     }
 
     /**
@@ -344,7 +341,7 @@ public static <T> Flowable<T> concat(
         Objects.requireNonNull(source1, "source1 is null");
         Objects.requireNonNull(source2, "source2 is null");
         Objects.requireNonNull(source3, "source3 is null");
-        return concat(Flowable.fromArray(source1, source2, source3));
+        return Flowable.fromArray(source1, source2, source3).concatMapSingleDelayError(Functions.identity(), false);
     }
 
     /**
@@ -383,7 +380,7 @@ public static <T> Flowable<T> concat(
         Objects.requireNonNull(source2, "source2 is null");
         Objects.requireNonNull(source3, "source3 is null");
         Objects.requireNonNull(source4, "source4 is null");
-        return concat(Flowable.fromArray(source1, source2, source3, source4));
+        return Flowable.fromArray(source1, source2, source3, source4).concatMapSingleDelayError(Functions.identity(), false);
     }
 
     /**
@@ -409,7 +406,7 @@ public static <T> Flowable<T> concat(
     @SchedulerSupport(SchedulerSupport.NONE)
     @SafeVarargs
     public static <T> Flowable<T> concatArray(@NonNull SingleSource<? extends T>... sources) {
-        return Flowable.fromArray(sources).concatMap(SingleInternalHelper.toFlowable(), 2);
+        return Flowable.fromArray(sources).concatMapSingleDelayError(Functions.identity(), false);
     }
 
     /**
@@ -435,7 +432,7 @@ public static <T> Flowable<T> concatArray(@NonNull SingleSource<? extends T>...
     @SchedulerSupport(SchedulerSupport.NONE)
     @SafeVarargs
     public static <T> Flowable<T> concatArrayDelayError(@NonNull SingleSource<? extends T>... sources) {
-        return Flowable.fromArray(sources).concatMapDelayError(SingleInternalHelper.toFlowable(), true, 2);
+        return Flowable.fromArray(sources).concatMapSingleDelayError(Functions.identity(), true);
     }
 
     /**
@@ -1091,7 +1088,7 @@ public static <T> Single<T> fromObservable(@NonNull ObservableSource<? extends T
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Flowable<T> merge(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources) {
-        return merge(Flowable.fromIterable(sources));
+        return Flowable.fromIterable(sources).flatMapSingle(Functions.identity());
     }
 
     /**
@@ -1129,10 +1126,9 @@ public static <T> Flowable<T> merge(@NonNull Iterable<@NonNull ? extends SingleS
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <T> Flowable<T> merge(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
         Objects.requireNonNull(sources, "sources is null");
-        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, SingleInternalHelper.toFlowable(), false, Integer.MAX_VALUE, Flowable.bufferSize()));
+        return RxJavaPlugins.onAssembly(new FlowableFlatMapSinglePublisher<>(sources, Functions.identity(), false, Integer.MAX_VALUE));
     }
 
     /**
@@ -1212,7 +1208,7 @@ public static <T> Flowable<T> merge(
      ) {
         Objects.requireNonNull(source1, "source1 is null");
         Objects.requireNonNull(source2, "source2 is null");
-        return merge(Flowable.fromArray(source1, source2));
+        return Flowable.fromArray(source1, source2).flatMapSingle(Functions.identity(), false, Integer.MAX_VALUE);
     }
 
     /**
@@ -1265,7 +1261,7 @@ public static <T> Flowable<T> merge(
         Objects.requireNonNull(source1, "source1 is null");
         Objects.requireNonNull(source2, "source2 is null");
         Objects.requireNonNull(source3, "source3 is null");
-        return merge(Flowable.fromArray(source1, source2, source3));
+        return Flowable.fromArray(source1, source2, source3).flatMapSingle(Functions.identity(), false, Integer.MAX_VALUE);
     }
 
     /**
@@ -1321,7 +1317,7 @@ public static <T> Flowable<T> merge(
         Objects.requireNonNull(source2, "source2 is null");
         Objects.requireNonNull(source3, "source3 is null");
         Objects.requireNonNull(source4, "source4 is null");
-        return merge(Flowable.fromArray(source1, source2, source3, source4));
+        return Flowable.fromArray(source1, source2, source3, source4).flatMapSingle(Functions.identity(), false, Integer.MAX_VALUE);
     }
 
     /**
@@ -1360,7 +1356,7 @@ public static <T> Flowable<T> merge(
     @SchedulerSupport(SchedulerSupport.NONE)
     @SafeVarargs
     public static <T> Flowable<T> mergeArray(SingleSource<? extends T>... sources) {
-        return Flowable.fromArray(sources).flatMapSingle(Functions.identity(), false, sources.length);
+        return Flowable.fromArray(sources).flatMapSingle(Functions.identity(), false, Math.max(1, sources.length));
     }
 
     /**
@@ -1396,7 +1392,7 @@ public static <T> Flowable<T> mergeArray(SingleSource<? extends T>... sources) {
     @SafeVarargs
     @NonNull
     public static <T> Flowable<T> mergeArrayDelayError(@NonNull SingleSource<? extends T>... sources) {
-        return Flowable.fromArray(sources).flatMapSingle(Functions.identity(), true, sources.length);
+        return Flowable.fromArray(sources).flatMapSingle(Functions.identity(), true, Math.max(1, sources.length));
     }
 
     /**
@@ -1423,7 +1419,7 @@ public static <T> Flowable<T> mergeArrayDelayError(@NonNull SingleSource<? exten
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Flowable<T> mergeDelayError(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources) {
-        return mergeDelayError(Flowable.fromIterable(sources));
+        return Flowable.fromIterable(sources).flatMapSingle(Functions.identity(), true, Integer.MAX_VALUE);
     }
 
     /**
@@ -1449,10 +1445,9 @@ public static <T> Flowable<T> mergeDelayError(@NonNull Iterable<@NonNull ? exten
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
-    @SuppressWarnings({ "unchecked", "rawtypes" })
     public static <T> Flowable<T> mergeDelayError(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
         Objects.requireNonNull(sources, "sources is null");
-        return RxJavaPlugins.onAssembly(new FlowableFlatMapPublisher(sources, SingleInternalHelper.toFlowable(), true, Integer.MAX_VALUE, Flowable.bufferSize()));
+        return RxJavaPlugins.onAssembly(new FlowableFlatMapSinglePublisher<>(sources, Functions.identity(), true, Integer.MAX_VALUE));
     }
 
     /**
@@ -1490,7 +1485,7 @@ public static <T> Flowable<T> mergeDelayError(
      ) {
         Objects.requireNonNull(source1, "source1 is null");
         Objects.requireNonNull(source2, "source2 is null");
-        return mergeDelayError(Flowable.fromArray(source1, source2));
+        return Flowable.fromArray(source1, source2).flatMapSingle(Functions.identity(), true, Integer.MAX_VALUE);
     }
 
     /**
@@ -1532,7 +1527,7 @@ public static <T> Flowable<T> mergeDelayError(
         Objects.requireNonNull(source1, "source1 is null");
         Objects.requireNonNull(source2, "source2 is null");
         Objects.requireNonNull(source3, "source3 is null");
-        return mergeDelayError(Flowable.fromArray(source1, source2, source3));
+        return Flowable.fromArray(source1, source2, source3).flatMapSingle(Functions.identity(), true, Integer.MAX_VALUE);
     }
 
     /**
@@ -1577,7 +1572,7 @@ public static <T> Flowable<T> mergeDelayError(
         Objects.requireNonNull(source2, "source2 is null");
         Objects.requireNonNull(source3, "source3 is null");
         Objects.requireNonNull(source4, "source4 is null");
-        return mergeDelayError(Flowable.fromArray(source1, source2, source3, source4));
+        return Flowable.fromArray(source1, source2, source3, source4).flatMapSingle(Functions.identity(), true, Integer.MAX_VALUE);
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapPublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapMaybePublisher.java
similarity index 53%
rename from src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapPublisher.java
rename to src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapMaybePublisher.java
index 0f5be8917d..f300607052 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapPublisher.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapMaybePublisher.java
@@ -15,31 +15,35 @@
 
 import org.reactivestreams.*;
 
-import io.reactivex.rxjava3.core.Flowable;
+import io.reactivex.rxjava3.core.*;
 import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.operators.flowable.FlowableFlatMapMaybe.FlatMapMaybeSubscriber;
+
+/**
+ * Maps upstream values into MaybeSources and merges their signals into one sequence.
+ * @param <T> the source value type
+ * @param <R> the result value type
+ */
+public final class FlowableFlatMapMaybePublisher<T, R> extends Flowable<R> {
 
-public final class FlowableFlatMapPublisher<T, U> extends Flowable<U> {
     final Publisher<T> source;
-    final Function<? super T, ? extends Publisher<? extends U>> mapper;
+
+    final Function<? super T, ? extends MaybeSource<? extends R>> mapper;
+
     final boolean delayErrors;
+
     final int maxConcurrency;
-    final int bufferSize;
 
-    public FlowableFlatMapPublisher(Publisher<T> source,
-            Function<? super T, ? extends Publisher<? extends U>> mapper,
-            boolean delayErrors, int maxConcurrency, int bufferSize) {
+    public FlowableFlatMapMaybePublisher(Publisher<T> source, Function<? super T, ? extends MaybeSource<? extends R>> mapper,
+            boolean delayError, int maxConcurrency) {
         this.source = source;
         this.mapper = mapper;
-        this.delayErrors = delayErrors;
+        this.delayErrors = delayError;
         this.maxConcurrency = maxConcurrency;
-        this.bufferSize = bufferSize;
     }
 
     @Override
-    protected void subscribeActual(Subscriber<? super U> s) {
-        if (FlowableScalarXMap.tryScalarXMapSubscribe(source, s, mapper)) {
-            return;
-        }
-        source.subscribe(FlowableFlatMap.subscribe(s, mapper, delayErrors, maxConcurrency, bufferSize));
+    protected void subscribeActual(Subscriber<? super R> s) {
+        source.subscribe(new FlatMapMaybeSubscriber<>(s, mapper, delayErrors, maxConcurrency));
     }
 }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapSinglePublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapSinglePublisher.java
new file mode 100644
index 0000000000..457a728523
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableFlatMapSinglePublisher.java
@@ -0,0 +1,49 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.flowable;
+
+import org.reactivestreams.*;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.operators.flowable.FlowableFlatMapSingle.FlatMapSingleSubscriber;
+
+/**
+ * Maps upstream values into SingleSources and merges their signals into one sequence.
+ * @param <T> the source value type
+ * @param <R> the result value type
+ */
+public final class FlowableFlatMapSinglePublisher<T, R> extends Flowable<R> {
+
+    final Publisher<T> source;
+
+    final Function<? super T, ? extends SingleSource<? extends R>> mapper;
+
+    final boolean delayErrors;
+
+    final int maxConcurrency;
+
+    public FlowableFlatMapSinglePublisher(Publisher<T> source, Function<? super T, ? extends SingleSource<? extends R>> mapper,
+            boolean delayError, int maxConcurrency) {
+        this.source = source;
+        this.mapper = mapper;
+        this.delayErrors = delayError;
+        this.maxConcurrency = maxConcurrency;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super R> s) {
+        source.subscribe(new FlatMapSingleSubscriber<>(s, mapper, delayErrors, maxConcurrency));
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapPublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapMaybePublisher.java
similarity index 51%
rename from src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapPublisher.java
rename to src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapMaybePublisher.java
index 8ee6afcd87..8651cdcb60 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapPublisher.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapMaybePublisher.java
@@ -10,40 +10,46 @@
  * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
  * the License for the specific language governing permissions and limitations under the License.
  */
-package io.reactivex.rxjava3.internal.operators.flowable;
+
+package io.reactivex.rxjava3.internal.operators.mixed;
 
 import org.reactivestreams.*;
 
-import io.reactivex.rxjava3.core.Flowable;
+import io.reactivex.rxjava3.core.*;
 import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.operators.mixed.FlowableConcatMapMaybe.ConcatMapMaybeSubscriber;
 import io.reactivex.rxjava3.internal.util.ErrorMode;
 
-public final class FlowableConcatMapPublisher<T, R> extends Flowable<R> {
+/**
+ * Maps each upstream item into a {@link MaybeSource}, subscribes to them one after the other terminates
+ * and relays their success values, optionally delaying any errors till the main and inner sources
+ * terminate.
+ * <p>History: 2.1.11 - experimental
+ * @param <T> the upstream element type
+ * @param <R> the output element type
+ * @since 2.2
+ */
+public final class FlowableConcatMapMaybePublisher<T, R> extends Flowable<R> {
 
     final Publisher<T> source;
 
-    final Function<? super T, ? extends Publisher<? extends R>> mapper;
-
-    final int prefetch;
+    final Function<? super T, ? extends MaybeSource<? extends R>> mapper;
 
     final ErrorMode errorMode;
 
-    public FlowableConcatMapPublisher(Publisher<T> source,
-            Function<? super T, ? extends Publisher<? extends R>> mapper,
-            int prefetch, ErrorMode errorMode) {
+    final int prefetch;
+
+    public FlowableConcatMapMaybePublisher(Publisher<T> source,
+            Function<? super T, ? extends MaybeSource<? extends R>> mapper,
+                    ErrorMode errorMode, int prefetch) {
         this.source = source;
         this.mapper = mapper;
-        this.prefetch = prefetch;
         this.errorMode = errorMode;
+        this.prefetch = prefetch;
     }
 
     @Override
     protected void subscribeActual(Subscriber<? super R> s) {
-
-        if (FlowableScalarXMap.tryScalarXMapSubscribe(source, s, mapper)) {
-            return;
-        }
-
-        source.subscribe(FlowableConcatMap.subscribe(s, mapper, prefetch, errorMode));
+        source.subscribe(new ConcatMapMaybeSubscriber<>(s, mapper, prefetch, errorMode));
     }
 }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapSinglePublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapSinglePublisher.java
new file mode 100644
index 0000000000..5b34314d81
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/FlowableConcatMapSinglePublisher.java
@@ -0,0 +1,55 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.mixed;
+
+import org.reactivestreams.*;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.operators.mixed.FlowableConcatMapSingle.ConcatMapSingleSubscriber;
+import io.reactivex.rxjava3.internal.util.ErrorMode;
+
+/**
+ * Maps each upstream item into a {@link SingleSource}, subscribes to them one after the other terminates
+ * and relays their success values, optionally delaying any errors till the main and inner sources
+ * terminate.
+ * <p>History: 2.1.11 - experimental
+ * @param <T> the upstream element type
+ * @param <R> the output element type
+ * @since 2.2
+ */
+public final class FlowableConcatMapSinglePublisher<T, R> extends Flowable<R> {
+
+    final Publisher<T> source;
+
+    final Function<? super T, ? extends SingleSource<? extends R>> mapper;
+
+    final ErrorMode errorMode;
+
+    final int prefetch;
+
+    public FlowableConcatMapSinglePublisher(Publisher<T> source,
+            Function<? super T, ? extends SingleSource<? extends R>> mapper,
+                    ErrorMode errorMode, int prefetch) {
+        this.source = source;
+        this.mapper = mapper;
+        this.errorMode = errorMode;
+        this.prefetch = prefetch;
+    }
+
+    @Override
+    protected void subscribeActual(Subscriber<? super R> s) {
+        source.subscribe(new ConcatMapSingleSubscriber<>(s, mapper, prefetch, errorMode));
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/ObservableConcatMapSingle.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/ObservableConcatMapSingle.java
index 5fc6b8a520..70d913cd42 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/ObservableConcatMapSingle.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/ObservableConcatMapSingle.java
@@ -36,7 +36,7 @@
  */
 public final class ObservableConcatMapSingle<T, R> extends Observable<R> {
 
-    final Observable<T> source;
+    final ObservableSource<T> source;
 
     final Function<? super T, ? extends SingleSource<? extends R>> mapper;
 
@@ -44,7 +44,7 @@ public final class ObservableConcatMapSingle<T, R> extends Observable<R> {
 
     final int prefetch;
 
-    public ObservableConcatMapSingle(Observable<T> source,
+    public ObservableConcatMapSingle(ObservableSource<T> source,
             Function<? super T, ? extends SingleSource<? extends R>> mapper,
                     ErrorMode errorMode, int prefetch) {
         this.source = source;
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelper.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelper.java
index 95ed46144c..47f8bf1e88 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelper.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelper.java
@@ -19,7 +19,6 @@
 import org.reactivestreams.Publisher;
 
 import io.reactivex.rxjava3.core.*;
-import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.functions.*;
 
 /**
@@ -105,19 +104,4 @@ public Iterator<Flowable<T>> iterator() {
     public static <T> Iterable<? extends Flowable<T>> iterableToFlowable(final Iterable<? extends SingleSource<? extends T>> sources) {
         return new ToFlowableIterable<>(sources);
     }
-
-    @SuppressWarnings("rawtypes")
-    enum ToObservable implements Function<SingleSource, Observable> {
-        INSTANCE;
-        @SuppressWarnings("unchecked")
-        @Override
-        public Observable apply(SingleSource v) {
-            return new SingleToObservable(v);
-        }
-    }
-
-    @SuppressWarnings({ "rawtypes", "unchecked" })
-    public static <T> Function<SingleSource<? extends T>, Observable<? extends T>> toObservable() {
-        return (Function)ToObservable.INSTANCE;
-    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelperTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelperTest.java
index e551b882d1..5d5e152c1b 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelperTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleInternalHelperTest.java
@@ -41,12 +41,6 @@ public void toFlowableEnum() {
         assertNotNull(SingleInternalHelper.ToFlowable.valueOf("INSTANCE"));
     }
 
-    @Test
-    public void toObservableEnum() {
-        assertEquals(1, SingleInternalHelper.ToObservable.values().length);
-        assertNotNull(SingleInternalHelper.ToObservable.valueOf("INSTANCE"));
-    }
-
     @Test
     public void singleIterableToFlowableIterable() {
         Iterable<? extends Flowable<Integer>> it = SingleInternalHelper.iterableToFlowable(
diff --git a/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java b/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java
index 94cf62d641..401bdcc918 100644
--- a/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java
+++ b/src/test/java/io/reactivex/rxjava3/maybe/MaybeTest.java
@@ -2514,8 +2514,6 @@ public void mergeArrayDelayError() {
         Maybe.mergeArrayDelayError(Maybe.error(new TestException()), Maybe.empty(), Maybe.just(1))
         .test()
         .assertFailure(TestException.class, 1);
-
-        assertSame(Flowable.empty(), Maybe.mergeArrayDelayError());
     }
 
     @Test

From b3516b2fbf76643d4fce2bb077de64deaf959f90 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Tue, 28 Jan 2020 16:32:12 +0100
Subject: [PATCH 32/37] 3.x: Fix marble dimensions, add program that checks
 them (#6890)

* 3.x: Fix marble dimensions, add program that checks them

* Remove an empty line.
---
 .../reactivex/rxjava3/core/Completable.java   |  26 ++--
 .../io/reactivex/rxjava3/core/Flowable.java   |  34 +++---
 .../java/io/reactivex/rxjava3/core/Maybe.java |  40 +++---
 .../io/reactivex/rxjava3/core/Observable.java | 114 +++++++++---------
 .../io/reactivex/rxjava3/core/Single.java     |  54 ++++-----
 .../rxjava3/parallel/ParallelFlowable.java    |   4 +-
 .../internal/util/MarbleDimensions.java       | 106 ++++++++++++++++
 7 files changed, 242 insertions(+), 136 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index 83e7848a51..cfdd87067d 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -178,7 +178,7 @@ public static Completable complete() {
     /**
      * Returns a {@code Completable} which completes only when all sources complete, one after another.
      * <p>
-     * <img width="640" height="283" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatArray.png" alt="">
+     * <img width="640" height="284" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatArray.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code concatArray} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -205,7 +205,7 @@ public static Completable concatArray(@NonNull CompletableSource... sources) {
     /**
      * Returns a {@code Completable} which completes only when all sources complete, one after another.
      * <p>
-     * <img width="640" height="322" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatArrayDelayError.png" alt="">
+     * <img width="640" height="324" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatArrayDelayError.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code concatArrayDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -247,7 +247,7 @@ public static Completable concat(@NonNull Iterable<@NonNull ? extends Completabl
     /**
      * Returns a {@code Completable} which completes only when all sources complete, one after another.
      * <p>
-     * <img width="640" height="237" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concat.p.png" alt="">
+     * <img width="640" height="238" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concat.p.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Completable} honors the backpressure of the downstream consumer
@@ -270,7 +270,7 @@ public static Completable concat(@NonNull Publisher<@NonNull ? extends Completab
     /**
      * Returns a {@code Completable} which completes only when all sources complete, one after another.
      * <p>
-     * <img width="640" height="237" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concat.pn.png" alt="">
+     * <img width="640" height="238" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concat.pn.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Completable} honors the backpressure of the downstream consumer
@@ -297,7 +297,7 @@ public static Completable concat(@NonNull Publisher<@NonNull ? extends Completab
     /**
      * Returns a {@code Completable} which completes only when all sources complete, one after another.
      * <p>
-     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatDelayError.png" alt="">
+     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.concatDelayError.i.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code concatDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -989,7 +989,7 @@ public static Completable mergeArrayDelayError(@NonNull CompletableSource... sou
      * any error emitted by any of the inner {@code CompletableSource}s until all of
      * them terminate in a way or another.
      * <p>
-     * <img width="640" height="475" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.mergeDelayError.png" alt="">
+     * <img width="640" height="476" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.mergeDelayError.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code mergeDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1200,7 +1200,7 @@ public static Completable switchOnNextDelayError(@NonNull Publisher<@NonNull ? e
      * Returns a {@code Completable} instance which manages a resource along
      * with a custom {@link CompletableSource} instance while the subscription is active.
      * <p>
-     * <img width="640" height="388" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.using.png" alt="">
+     * <img width="640" height="389" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.using.png" alt="">
      * <p>
      * This overload disposes eagerly before the terminal event is emitted.
      * <dl>
@@ -1294,7 +1294,7 @@ public static Completable wrap(@NonNull CompletableSource source) {
      * Returns a {@code Completable} that emits the a terminated event of either this {@code Completable}
      * or the other {@link CompletableSource}, whichever fires first.
      * <p>
-     * <img width="640" height="484" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.ambWith.png" alt="">
+     * <img width="640" height="485" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.ambWith.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code ambWith} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1395,7 +1395,7 @@ public final Completable ambWith(@NonNull CompletableSource other) {
      * propagated to the downstream observer and will result in skipping the subscription to the next
      * {@code MaybeSource}.
      * <p>
-     * <img width="640" height="280" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.andThen.m.png" alt="">
+     * <img width="640" height="281" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.andThen.m.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code andThen} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1443,7 +1443,7 @@ public final Completable andThen(@NonNull CompletableSource next) {
      * Subscribes to and awaits the termination of this {@code Completable} instance in a blocking manner and
      * rethrows any exception emitted.
      * <p>
-     * <img width="640" height="432" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingAwait.png" alt="">
+     * <img width="640" height="433" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingAwait.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code blockingAwait} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1665,7 +1665,7 @@ public final Completable concatWith(@NonNull CompletableSource other) {
     /**
      * Returns a {@code Completable} which delays the emission of the completion event by the given time.
      * <p>
-     * <img width="640" height="343" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.delay.png" alt="">
+     * <img width="640" height="344" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.delay.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code delay} does operate by default on the {@code computation} {@link Scheduler}.</dd>
@@ -1955,7 +1955,7 @@ public final Completable doOnSubscribe(@NonNull Consumer<? super Disposable> onS
      * Returns a {@code Completable} instance that calls the given {@code onTerminate} {@link Action} just before this {@code Completable}
      * completes normally or with an exception.
      * <p>
-     * <img width="640" height="304" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.doOnTerminate.png" alt="">
+     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.doOnTerminate.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code doOnTerminate} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1978,7 +1978,7 @@ public final Completable doOnTerminate(@NonNull Action onTerminate) {
      * Returns a {@code Completable} instance that calls the given {@code onAfterTerminate}  {@link Action} after this {@code Completable}
      * completes normally or with an exception.
      * <p>
-     * <img width="640" height="304" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.doAfterTerminate.png" alt="">
+     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.doAfterTerminate.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code doAfterTerminate} does not operate by default on a particular {@link Scheduler}.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 453c9e4bba..58ffd3d6f8 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -1964,7 +1964,7 @@ public static <T> Flowable<T> error(@NonNull Throwable throwable) {
      * Returns a {@code Flowable} instance that runs the given {@link Action} for each subscriber and
      * emits either its exception or simply completes.
      * <p>
-     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromAction.png" alt="">
+     * <img width="640" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.fromAction.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This source doesn't produce any elements and effectively ignores downstream backpressure.</dd>
@@ -9934,7 +9934,7 @@ public final Flowable<T> filter(@NonNull Predicate<? super T> predicate) {
      * Returns a {@link Maybe} that emits only the very first item emitted by this {@code Flowable} or
      * completes if this {@code Flowable} is empty.
      * <p>
-     * <img width="640" height="237" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/firstElement.m.png" alt="">
+     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/firstElement.m.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream and consumes the current {@code Flowable} in a bounded manner.</dd>
@@ -9957,7 +9957,7 @@ public final Maybe<T> firstElement() {
      * Returns a {@link Single} that emits only the very first item emitted by this {@code Flowable}, or a default
      * item if this {@code Flowable} completes without emitting anything.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/first.s.png" alt="">
+     * <img width="640" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/first.s.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream and consumes the current {@code Flowable} in a bounded manner.</dd>
@@ -10561,7 +10561,7 @@ public final Completable flatMapCompletable(@NonNull Function<? super T, ? exten
      * Merges {@link Iterable}s generated by a mapper {@link Function} for each individual item emitted by
      * the current {@code Flowable} into a single {@code Flowable} sequence.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
+     * <img width="640" height="342" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream. The current {@code Flowable}s is
@@ -10592,7 +10592,7 @@ public final <U> Flowable<U> flatMapIterable(@NonNull Function<? super T, ? exte
      * Merges {@link Iterable}s generated by a mapper {@link Function} for each individual item emitted by
      * the current {@code Flowable} into a single {@code Flowable} sequence.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
+     * <img width="640" height="342" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream. The current {@code Flowable}s is
@@ -14336,7 +14336,7 @@ public final Flowable<T> sample(long period, @NonNull TimeUnit unit) {
      * Returns a {@code Flowable} that emits the most recently emitted item (if any) emitted by the current {@code Flowable}
      * within periodic time intervals and optionally emit the very last upstream item when the upstream completes.
      * <p>
-     * <img width="640" height="276" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.emitlast.png" alt="">
+     * <img width="640" height="277" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.emitlast.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This operator does not support backpressure as it uses time to control data flow.</dd>
@@ -14407,7 +14407,7 @@ public final Flowable<T> sample(long period, @NonNull TimeUnit unit, @NonNull Sc
      * within periodic time intervals, where the intervals are defined on a particular {@link Scheduler}
      * and optionally emit the very last upstream item when the upstream completes.
      * <p>
-     * <img width="640" height="276" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.s.emitlast.png" alt="">
+     * <img width="640" height="277" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.s.emitlast.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This operator does not support backpressure as it uses time to control data flow.</dd>
@@ -14448,7 +14448,7 @@ public final Flowable<T> sample(long period, @NonNull TimeUnit unit, @NonNull Sc
      * emits the most recently emitted item (if any) emitted by the current {@code Flowable} since the previous
      * emission from the {@code sampler} {@code Publisher}.
      * <p>
-     * <img width="640" height="289" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.nolast.png" alt="">
+     * <img width="640" height="290" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.nolast.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This operator does not support backpressure as it uses the emissions of the {@code sampler}
@@ -14480,7 +14480,7 @@ public final <U> Flowable<T> sample(@NonNull Publisher<U> sampler) {
      * emission from the {@code sampler} {@code Publisher}
      * and optionally emit the very last upstream item when the upstream or other {@code Publisher} complete.
      * <p>
-     * <img width="640" height="289" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.emitlast.png" alt="">
+     * <img width="640" height="290" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.emitlast.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This operator does not support backpressure as it uses the emissions of the {@code sampler}
@@ -14759,7 +14759,7 @@ public final Single<T> single(@NonNull T defaultItem) {
      * if this {@code Flowable} completes without emitting any items a {@link NoSuchElementException} will be signaled and
      * if this {@code Flowable} emits more than one item, an {@link IllegalArgumentException} will be signaled.
      * <p>
-     * <img width="640" height="205" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/singleOrError.png" alt="">
+     * <img width="640" height="206" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/singleOrError.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream and consumes the current {@code Flowable} in an
@@ -15728,7 +15728,7 @@ public final Flowable<T> subscribeOn(@NonNull Scheduler scheduler, boolean reque
      * Returns a {@code Flowable} that emits the items emitted by the current {@code Flowable} or the items of an alternate
      * {@link Publisher} if the current {@code Flowable} is empty.
      * <p>
-     * <img width="640" height="255" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.png" alt="">
+     * <img width="640" height="256" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>If the current {@code Flowable} is empty, the alternate {@code Publisher} is expected to honor backpressure.
@@ -15835,7 +15835,7 @@ public final <R> Flowable<R> switchMap(@NonNull Function<? super T, ? extends Pu
      * disposing the subscription to the previous {@code CompletableSource}, thus keeping at most one
      * active {@code CompletableSource} running.
      * <p>
-     * <img width="640" height="521" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapCompletable.f.png" alt="">
+     * <img width="640" height="522" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapCompletable.f.png" alt="">
      * <p>
      * Since a {@code CompletableSource} doesn't produce any items, the resulting reactive type of
      * this operator is a {@link Completable} that can only indicate successful completion or
@@ -16852,7 +16852,7 @@ public final Flowable<T> throttleLast(long intervalDuration, @NonNull TimeUnit u
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.png" alt="">
      * <p>
      * Unlike the option with {@link #throttleLatest(long, TimeUnit, boolean)}, the very last item being held back
      * (if any) is not emitted when the upstream completes.
@@ -16891,7 +16891,7 @@ public final Flowable<T> throttleLatest(long timeout, @NonNull TimeUnit unit) {
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.e.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.e.png" alt="">
      * <p>
      * If no items were emitted from the upstream during this timeout phase, the next
      * upstream item is emitted immediately and the timeout window starts from then.
@@ -16930,7 +16930,7 @@ public final Flowable<T> throttleLatest(long timeout, @NonNull TimeUnit unit, bo
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.s.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.s.png" alt="">
      * <p>
      * Unlike the option with {@link #throttleLatest(long, TimeUnit, Scheduler, boolean)}, the very last item being held back
      * (if any) is not emitted when the upstream completes.
@@ -16970,7 +16970,7 @@ public final Flowable<T> throttleLatest(long timeout, @NonNull TimeUnit unit, @N
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.se.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.se.png" alt="">
      * <p>
      * If no items were emitted from the upstream during this timeout phase, the next
      * upstream item is emitted immediately and the timeout window starts from then.
@@ -19764,7 +19764,7 @@ public final CompletionStage<T> lastStage(@Nullable T defaultItem) {
      * Signals the first upstream item or a {@link NoSuchElementException} if the upstream is empty via
      * a {@link CompletionStage}.
      * <p>
-     * <img width="640" height="338" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/firstOrErrorStage.f.png" alt="">
+     * <img width="640" height="343" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/firstOrErrorStage.f.png" alt="">
      * <p>
      * The upstream can be canceled by converting the resulting {@code CompletionStage} into
      * {@link CompletableFuture} via {@link CompletionStage#toCompletableFuture()} and
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index d4116406b4..37ce1e99e2 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -117,7 +117,7 @@ public abstract class Maybe<T> implements MaybeSource<T> {
      * Runs multiple {@link MaybeSource}s provided by an {@link Iterable} sequence and
      * signals the events of the first one that signals (disposing the rest).
      * <p>
-     * <img width="640" height="519" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.amb.png" alt="">
+     * <img width="640" height="518" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.amb.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code amb} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -196,7 +196,7 @@ public static <T> Flowable<T> concat(@NonNull Iterable<@NonNull ? extends MaybeS
     /**
      * Returns a {@link Flowable} that emits the items emitted by two {@link MaybeSource}s, one after the other.
      * <p>
-     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concat.png" alt="">
+     * <img width="640" height="423" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concat.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
@@ -226,7 +226,7 @@ public static <T> Flowable<T> concat(@NonNull MaybeSource<? extends T> source1,
     /**
      * Returns a {@link Flowable} that emits the items emitted by three {@link MaybeSource}s, one after the other.
      * <p>
-     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concat.png" alt="">
+     * <img width="640" height="423" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concat.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
@@ -260,7 +260,7 @@ public static <T> Flowable<T> concat(
     /**
      * Returns a {@link Flowable} that emits the items emitted by four {@link MaybeSource}s, one after the other.
      * <p>
-     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concat.png" alt="">
+     * <img width="640" height="423" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concat.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
@@ -425,7 +425,7 @@ public static <T> Flowable<T> concatArrayDelayError(@NonNull MaybeSource<? exten
      * source {@code MaybeSource}s. The operator buffers the value emitted by these {@code MaybeSource}s and then drains them
      * in order, each one after the previous one completes.
      * <p>
-     * <img width="640" height="489" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatArrayEager.png" alt="">
+     * <img width="640" height="490" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatArrayEager.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -1227,7 +1227,7 @@ public static <T> Flowable<T> merge(@NonNull Publisher<@NonNull ? extends MaybeS
      * Flattens a {@link MaybeSource} that emits a {@code MaybeSource} into a single {@code MaybeSource} that emits the item
      * emitted by the nested {@code MaybeSource}, without any transformation.
      * <p>
-     * <img width="640" height="393" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.oo.png" alt="">
+     * <img width="640" height="394" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.merge.oo.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1771,7 +1771,7 @@ public static <T> Maybe<T> never() {
      * Returns a {@link Single} that emits a {@link Boolean} value that indicates whether two {@link MaybeSource} sequences are the
      * same by comparing the items emitted by each {@code MaybeSource} pairwise.
      * <p>
-     * <img width="640" height="196" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.sequenceEqual.png" alt="">
+     * <img width="640" height="187" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.sequenceEqual.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code sequenceEqual} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2562,7 +2562,7 @@ public static <T1, T2, T3, T4, T5, T6, T7, T8, T9, R> Maybe<R> zip(
      * {@code Function<Integer[], R>} passed to the method would trigger a {@link ClassCastException}.
      *
      * <p>
-     * <img width="640" height="341" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.zipArray.png" alt="">
+     * <img width="640" height="340" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.zipArray.png" alt="">
      * <p>This operator terminates eagerly if any of the source {@code MaybeSource}s signal an {@code onError} or {@code onComplete}. This
      * also means it is possible some sources may not get subscribed to at all.
      * <dl>
@@ -3630,7 +3630,7 @@ public final Maybe<T> filter(@NonNull Predicate<? super T> predicate) {
      * Returns a {@code Maybe} that is based on applying a specified function to the item emitted by the current {@code Maybe},
      * where that function returns a {@link MaybeSource}.
      * <p>
-     * <img width="640" height="356" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.png" alt="">
+     * <img width="640" height="357" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3782,7 +3782,7 @@ public final <U> Observable<U> flattenAsObservable(@NonNull Function<? super T,
      * Returns an {@link Observable} that is based on applying a specified function to the item emitted by the current {@code Maybe},
      * where that function returns an {@link ObservableSource}.
      * <p>
-     * <img width="640" height="356" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.png" alt="">
+     * <img width="640" height="357" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapObservable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3807,7 +3807,7 @@ public final <R> Observable<R> flatMapObservable(@NonNull Function<? super T, ?
      * Returns a {@link Flowable} that emits items based on applying a specified function to the item emitted by the
      * current {@code Maybe}, where that function returns a {@link Publisher}.
      * <p>
-     * <img width="640" height="260" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapPublisher.png" alt="">
+     * <img width="640" height="261" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapPublisher.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the downstream backpressure.</dd>
@@ -3864,7 +3864,7 @@ public final <R> Single<R> flatMapSingle(@NonNull Function<? super T, ? extends
      * current {@code Maybe}, where that function returns a {@link Single}.
      * When this {@code Maybe} just completes the resulting {@code Maybe} completes as well.
      * <p>
-     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle.png" alt="">
+     * <img width="640" height="357" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapSingleElement} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3935,7 +3935,7 @@ public final Maybe<T> hide() {
     /**
      * Returns a {@link Completable} that ignores the item emitted by the current {@code Maybe} and only calls {@code onComplete} or {@code onError}.
      * <p>
-     * <img width="640" height="389" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.ignoreElement.png" alt="">
+     * <img width="640" height="390" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.ignoreElement.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code ignoreElement} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4207,7 +4207,7 @@ public final Flowable<T> mergeWith(@NonNull MaybeSource<? extends T> other) {
      * Wraps a {@code Maybe} to emit its item (or notify of its error) on a specified {@link Scheduler},
      * asynchronously.
      * <p>
-     * <img width="640" height="182" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.observeOn.png" alt="">
+     * <img width="640" height="183" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.observeOn.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>you specify which {@code Scheduler} this operator will use.</dd>
@@ -5137,7 +5137,7 @@ public final void subscribe(@NonNull MaybeObserver<? super T> observer) {
     /**
      * Asynchronously subscribes subscribers to this {@code Maybe} on the specified {@link Scheduler}.
      * <p>
-     * <img width="640" height="752" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.subscribeOn.png" alt="">
+     * <img width="640" height="753" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.subscribeOn.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>you specify which {@code Scheduler} this operator will use.</dd>
@@ -5194,7 +5194,7 @@ public final Maybe<T> subscribeOn(@NonNull Scheduler scheduler) {
      * Returns a {@code Maybe} that emits the items emitted by the current {@code Maybe} or the items of an alternate
      * {@link MaybeSource} if the current {@code Maybe} is empty.
      * <p>
-     * <img width="640" height="445" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.m.png" alt="">
+     * <img width="640" height="446" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.m.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchIfEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5217,7 +5217,7 @@ public final Maybe<T> switchIfEmpty(@NonNull MaybeSource<? extends T> other) {
      * Returns a {@link Single} that emits the items emitted by the current {@code Maybe} or the item of an alternate
      * {@link SingleSource} if the current {@code Maybe} is empty.
      * <p>
-     * <img width="640" height="445" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.m.png" alt="">
+     * <img width="640" height="446" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.m.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchIfEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5739,7 +5739,7 @@ public final <U> Maybe<T> timeout(@NonNull Publisher<U> timeoutIndicator, @NonNu
      * Returns a {@code Maybe} which makes sure when a {@link MaybeObserver} disposes the {@link Disposable},
      * that call is propagated up on the specified {@link Scheduler}.
      * <p>
-     * <img width="640" height="700" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.unsubscribeOn.png" alt="">
+     * <img width="640" height="693" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.unsubscribeOn.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code unsubscribeOn} calls {@code dispose()} of the upstream on the {@code Scheduler} you specify.</dd>
@@ -6002,7 +6002,7 @@ public final CompletionStage<T> toCompletionStage(@Nullable T defaultItem) {
      * Maps the upstream succecss value into a Java {@link Stream} and emits its
      * items to the downstream consumer as a {@link Flowable}.
      * <p>
-     * <img width="640" height="247" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flattenStreamAsFlowable.m.png" alt="">
+     * <img width="640" height="246" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flattenStreamAsFlowable.m.png" alt="">
      * <p>
      * The operator closes the {@code Stream} upon cancellation and when it terminates. The exceptions raised when
      * closing a {@code Stream} are routed to the global error handler ({@link RxJavaPlugins#onError(Throwable)}.
@@ -6046,7 +6046,7 @@ public final <R> Flowable<R> flattenStreamAsFlowable(@NonNull Function<? super T
     /**
      * Maps the upstream succecss value into a Java {@link Stream} and emits its
      * items to the downstream consumer as an {@link Observable}.
-     * <img width="640" height="247" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flattenStreamAsObservable.m.png" alt="">
+     * <img width="640" height="241" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flattenStreamAsObservable.m.png" alt="">
      * <p>
      * The operator closes the {@code Stream} upon cancellation and when it terminates. The exceptions raised when
      * closing a {@code Stream} are routed to the global error handler ({@link RxJavaPlugins#onError(Throwable)}.
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index 6db7ce3cc1..9eeb169871 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -1271,7 +1271,7 @@ public static <T> Observable<T> concatArrayDelayError(@NonNull ObservableSource<
     /**
      * Concatenates an array of {@link ObservableSource}s eagerly into a single stream of values.
      * <p>
-     * <img width="640" height="410" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatArrayEager.png" alt="">
+     * <img width="640" height="411" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatArrayEager.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * {@code ObservableSource}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them
@@ -1688,7 +1688,7 @@ public static <T> Observable<T> empty() {
      * Returns an {@code Observable} that invokes an {@link Observer}'s {@link Observer#onError onError} method when the
      * {@code Observer} subscribes to it.
      * <p>
-     * <img width="640" height="220" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/error.supplier.png" alt="">
+     * <img width="640" height="221" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/error.supplier.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1714,7 +1714,7 @@ public static <T> Observable<T> error(@NonNull Supplier<? extends Throwable> sup
      * Returns an {@code Observable} that invokes an {@link Observer}'s {@link Observer#onError onError} method when the
      * {@code Observer} subscribes to it.
      * <p>
-     * <img width="640" height="220" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/error.item.png" alt="">
+     * <img width="640" height="221" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/error.item.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1740,7 +1740,7 @@ public static <T> Observable<T> error(@NonNull Throwable throwable) {
      * Returns an {@code Observable} instance that runs the given {@link Action} for each subscriber and
      * emits either its exception or simply completes.
      * <p>
-     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromAction.png" alt="">
+     * <img width="640" height="287" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.fromAction.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code fromAction} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1941,7 +1941,7 @@ public static <T> Observable<T> fromFuture(@NonNull Future<? extends T> future,
     /**
      * Converts an {@link Iterable} sequence into an {@code Observable} that emits the items in the sequence.
      * <p>
-     * <img width="640" height="186" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/fromIterable.png" alt="">
+     * <img width="640" height="187" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/fromIterable.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code fromIterable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5198,7 +5198,7 @@ public static <T, R> Observable<R> zipArray(
      * Returns a {@link Single} that emits a {@link Boolean} that indicates whether all of the items emitted by the current
      * {@code Observable} satisfy a condition.
      * <p>
-     * <img width="640" height="264" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/all.o.png" alt="">
+     * <img width="640" height="265" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/all.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code all} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5275,7 +5275,7 @@ public final Single<Boolean> any(@NonNull Predicate<? super T> predicate) {
      * Returns the first item emitted by the current {@code Observable}, or throws
      * {@link NoSuchElementException} if it emits no items.
      * <p>
-     * <img width="640" height="412" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/blockingFirst.o.png" alt="">
+     * <img width="640" height="413" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/blockingFirst.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code blockingFirst} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5703,7 +5703,7 @@ public final void blockingSubscribe() {
     /**
      * Subscribes to the source and calls the given callbacks <strong>on the current thread</strong>.
      * <p>
-     * <img width="640" height="393" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/blockingSubscribe.o.1.png" alt="">
+     * <img width="640" height="394" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/blockingSubscribe.o.1.png" alt="">
      * <p>
      * If the {@code Observable} emits an error, it is wrapped into an
      * {@link OnErrorNotImplementedException}
@@ -5732,7 +5732,7 @@ public final void blockingSubscribe(@NonNull Consumer<? super T> onNext) {
     /**
      * Subscribes to the source and calls the given callbacks <strong>on the current thread</strong>.
      * <p>
-     * <img width="640" height="396" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/blockingSubscribe.o.2.png" alt="">
+     * <img width="640" height="397" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/blockingSubscribe.o.2.png" alt="">
      * <p>
      * Note that calling this method will block the caller thread until the upstream terminates
      * normally or with an error. Therefore, calling this method from special threads such as the
@@ -6748,7 +6748,7 @@ public final <R> Observable<R> concatMap(@NonNull Function<? super T, ? extends
      * while delaying any error from either this or any of the inner {@code ObservableSource}s
      * till all of them terminate.
      * <p>
-     * <img width="640" height="347" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapDelayError.o.png" alt="">
+     * <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapDelayError.o.png" alt="">
      * <p>
      * Note that there is no guarantee where the given {@code mapper} function will be executed; it could be on the subscribing thread,
      * on the upstream thread signaling the new item to be mapped or on the thread where the inner source terminates. To ensure
@@ -6777,7 +6777,7 @@ public final <R> Observable<R> concatMapDelayError(@NonNull Function<? super T,
      * while delaying any error from either this or any of the inner {@code ObservableSource}s
      * till all of them terminate.
      * <p>
-     * <img width="640" height="347" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapDelayError.o.png" alt="">
+     * <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapDelayError.o.png" alt="">
      * <p>
      * Note that there is no guarantee where the given {@code mapper} function will be executed; it could be on the subscribing thread,
      * on the upstream thread signaling the new item to be mapped or on the thread where the inner source terminates. To ensure
@@ -6823,7 +6823,7 @@ public final <R> Observable<R> concatMapDelayError(@NonNull Function<? super T,
      * while delaying any error from either this or any of the inner {@code ObservableSource}s
      * till all of them terminate.
      * <p>
-     * <img width="640" height="347" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapDelayError.o.png" alt="">
+     * <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapDelayError.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code concatMapDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -6863,7 +6863,7 @@ public final <R> Observable<R> concatMapDelayError(@NonNull Function<? super T,
      * current {@code Observable}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them in
      * order, each one after the previous one completes.
      * <p>
-     * <img width="640" height="360" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapEager.o.png" alt="">
+     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapEager.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
@@ -6890,7 +6890,7 @@ public final <R> Observable<R> concatMapEager(@NonNull Function<? super T, ? ext
      * current {@code Observable}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them in
      * order, each one after the previous one completes.
      * <p>
-     * <img width="640" height="360" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapEager.o.png" alt="">
+     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapEager.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
@@ -6990,7 +6990,7 @@ public final <R> Observable<R> concatMapEagerDelayError(@NonNull Function<? supe
      * Maps each element of the current {@code Observable} into {@link CompletableSource}s, subscribes to them one at a time in
      * order and waits until the upstream and all {@code CompletableSource}s complete.
      * <p>
-     * <img width="640" height="505" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapCompletable.o.png" alt="">
+     * <img width="640" height="506" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapCompletable.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code concatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -7013,7 +7013,7 @@ public final Completable concatMapCompletable(@NonNull Function<? super T, ? ext
      * Maps each element of the current {@code Observable} into {@link CompletableSource}s, subscribes to them one at a time in
      * order and waits until the upstream and all {@code CompletableSource}s complete.
      * <p>
-     * <img width="640" height="505" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapCompletable.o.png" alt="">
+     * <img width="640" height="506" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatMapCompletable.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code concatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -8366,7 +8366,7 @@ public final Observable<T> doAfterTerminate(@NonNull Action onAfterTerminate) {
      * <p>Note that the {@code onFinally} action is shared between subscriptions and as such
      * should be thread-safe.
      * <p>
-     * <img width="640" height="281" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doFinally.o.png" alt="">
+     * <img width="640" height="282" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doFinally.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code doFinally} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -8686,7 +8686,7 @@ public final Maybe<T> elementAt(long index) {
      * Returns a {@link Single} that emits the item found at a specified index in a sequence of emissions from
      * the current {@code Observable}, or a default item if that index is out of range.
      * <p>
-     * <img width="640" height="353" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/elementAtDefault.o.png" alt="">
+     * <img width="640" height="354" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/elementAtDefault.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code elementAt} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -8788,7 +8788,7 @@ public final Maybe<T> firstElement() {
      * Returns a {@link Single} that emits only the very first item emitted by the current {@code Observable}, or a default item
      * if the current {@code Observable} completes without emitting any items.
      * <p>
-     * <img width="640" height="286" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/first.s.png" alt="">
+     * <img width="640" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/first.s.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code first} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -8811,7 +8811,7 @@ public final Single<T> first(@NonNull T defaultItem) {
      * Returns a {@link Single} that emits only the very first item emitted by the current {@code Observable} or
      * signals a {@link NoSuchElementException} if the current {@code Observable} is empty.
      * <p>
-     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/firstOrError.o.png" alt="">
+     * <img width="640" height="435" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/firstOrError.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code firstOrError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -8888,7 +8888,7 @@ public final <R> Observable<R> flatMap(@NonNull Function<? super T, ? extends Ob
      * {@code ObservableSource}s and emitting the results of this merger, while limiting the maximum number of concurrent
      * subscriptions to these {@code ObservableSource}s.
      * <p>
-     * <img width="640" height="441" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapMaxConcurrency.o.png" alt="">
+     * <img width="640" height="442" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapMaxConcurrency.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -8922,7 +8922,7 @@ public final <R> Observable<R> flatMap(@NonNull Function<? super T, ? extends Ob
      * {@code ObservableSource}s and emitting the results of this merger, while limiting the maximum number of concurrent
      * subscriptions to these {@code ObservableSource}s.
      * <p>
-     * <img width="640" height="441" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapMaxConcurrency.o.png" alt="">
+     * <img width="640" height="442" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapMaxConcurrency.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -9050,7 +9050,7 @@ public final <R> Observable<R> flatMap(
      * {@code ObservableSource}s and emitting the results of this merger, while limiting the maximum number of concurrent
      * subscriptions to these {@code ObservableSource}s.
      * <p>
-     * <img width="640" height="441" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapMaxConcurrency.o.png" alt="">
+     * <img width="640" height="442" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapMaxConcurrency.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -9282,7 +9282,7 @@ public final Completable flatMapCompletable(@NonNull Function<? super T, ? exten
      * Maps each element of the current {@code Observable} into {@link CompletableSource}s, subscribes to them and
      * waits until the upstream and all {@code CompletableSource}s complete, optionally delaying all errors.
      * <p>
-     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapCompletableDelayError.o.png" alt="">
+     * <img width="640" height="362" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapCompletableDelayError.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code flatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -9487,7 +9487,7 @@ public final Disposable forEach(@NonNull Consumer<? super T> onNext) {
      * Subscribes to the {@link ObservableSource} and calls a {@link Predicate} for each item of the current {@code Observable},
      * on its emission thread, until the predicate returns {@code false}.
      * <p>
-     * <img width="640" height="272" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/forEachWhile.o.png" alt="">
+     * <img width="640" height="273" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/forEachWhile.o.png" alt="">
      * <p>
      * If the {@code Observable} emits an error, it is wrapped into an
      * {@link OnErrorNotImplementedException}
@@ -10668,7 +10668,7 @@ public final Observable<T> onErrorReturnItem(@NonNull T item) {
      * Nulls out references to the upstream producer and downstream {@link Observer} if
      * the sequence is terminated or downstream calls {@code dispose()}.
      * <p>
-     * <img width="640" height="246" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onTerminateDetach.o.png" alt="">
+     * <img width="640" height="247" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onTerminateDetach.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code onTerminateDetach} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -10923,7 +10923,7 @@ public final Observable<T> repeat(long times) {
      * Returns an {@code Observable} that repeats the sequence of items emitted by the current {@code Observable} until
      * the provided stop function returns {@code true}.
      * <p>
-     * <img width="640" height="262" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeatUntil.o.png" alt="">
+     * <img width="640" height="263" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeatUntil.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code repeatUntil} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11031,7 +11031,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * Note that due to concurrency requirements, {@code replay(bufferSize)} may hold strong references to more than
      * {@code bufferSize} source emissions.
      * <p>
-     * <img width="640" height="391" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fn.png" alt="">
+     * <img width="640" height="392" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fn.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code replay} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11067,7 +11067,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * Note that due to concurrency requirements, {@code replay(bufferSize)} may hold strong references to more than
      * {@code bufferSize} source emissions.
      * <p>
-     * <img width="640" height="391" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fn.png" alt="">
+     * <img width="640" height="392" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fn.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code replay} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11142,7 +11142,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * Note that due to concurrency requirements, {@code replay(bufferSize)} may hold strong references to more than
      * {@code bufferSize} source emissions.
      * <p>
-     * <img width="640" height="328" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fnts.png" alt="">
+     * <img width="640" height="329" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fnts.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
@@ -11189,7 +11189,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * Note that due to concurrency requirements, {@code replay(bufferSize)} may hold strong references to more than
      * {@code bufferSize} source emissions.
      * <p>
-     * <img width="640" height="328" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fnts.png" alt="">
+     * <img width="640" height="329" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fnts.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
@@ -11234,7 +11234,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * emitted by a {@link ConnectableObservable} that shares a single subscription to the current {@code Observable},
      * replaying all items that were emitted within a specified time window.
      * <p>
-     * <img width="640" height="393" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.ft.png" alt="">
+     * <img width="640" height="394" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.ft.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code replay} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -11265,7 +11265,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * emitted by a {@link ConnectableObservable} that shares a single subscription to the current {@code Observable},
      * replaying all items that were emitted within a specified time window.
      * <p>
-     * <img width="640" height="366" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fts.png" alt="">
+     * <img width="640" height="367" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fts.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
@@ -11302,7 +11302,7 @@ public final <R> Observable<R> replay(@NonNull Function<? super Observable<T>, ?
      * emitted by a {@link ConnectableObservable} that shares a single subscription to the current {@code Observable},
      * replaying all items that were emitted within a specified time window.
      * <p>
-     * <img width="640" height="366" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fts.png" alt="">
+     * <img width="640" height="367" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fts.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@link Scheduler} this operator will use.</dd>
@@ -11654,7 +11654,7 @@ public final Observable<T> retry() {
      * Returns an {@code Observable} that mirrors the current {@code Observable}, resubscribing to it if it calls {@code onError}
      * and the predicate returns {@code true} for that specific exception and retry count.
      * <p>
-     * <img width="640" height="235" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.ne.png" alt="">
+     * <img width="640" height="236" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.ne.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11681,7 +11681,7 @@ public final Observable<T> retry(@NonNull BiPredicate<? super Integer, ? super T
      * Returns an {@code Observable} that mirrors the current {@code Observable}, resubscribing to it if it calls {@code onError}
      * up to a specified number of retries.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.n.png" alt="">
+     * <img width="640" height="327" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.n.png" alt="">
      * <p>
      * If the current {@code Observable} calls {@link Observer#onError}, this method will resubscribe to the current
      * {@code Observable} for a maximum of {@code count} resubscriptions rather than propagating the
@@ -11712,7 +11712,7 @@ public final Observable<T> retry(long times) {
     /**
      * Retries at most times or until the predicate returns {@code false}, whichever happens first.
      * <p>
-     * <img width="640" height="269" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.nfe.png" alt="">
+     * <img width="640" height="270" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.nfe.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11738,7 +11738,7 @@ public final Observable<T> retry(long times, @NonNull Predicate<? super Throwabl
     /**
      * Retries the current {@code Observable} if the predicate returns {@code true}.
      * <p>
-     * <img width="640" height="248" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.e.png" alt="">
+     * <img width="640" height="249" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.o.e.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11758,7 +11758,7 @@ public final Observable<T> retry(@NonNull Predicate<? super Throwable> predicate
     /**
      * Retries until the given stop function returns {@code true}.
      * <p>
-     * <img width="640" height="261" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retryUntil.o.png" alt="">
+     * <img width="640" height="262" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retryUntil.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -11911,7 +11911,7 @@ public final Observable<T> sample(long period, @NonNull TimeUnit unit) {
      * Returns an {@code Observable} that emits the most recently emitted item (if any) emitted by the current {@code Observable}
      * within periodic time intervals and optionally emit the very last upstream item when the upstream completes.
      * <p>
-     * <img width="640" height="276" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.emitlast.png" alt="">
+     * <img width="640" height="277" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.emitlast.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code sample} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -11974,7 +11974,7 @@ public final Observable<T> sample(long period, @NonNull TimeUnit unit, @NonNull
      * within periodic time intervals, where the intervals are defined on a particular {@link Scheduler}
      *  and optionally emit the very last upstream item when the upstream completes.
      * <p>
-     * <img width="640" height="276" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.s.emitlast.png" alt="">
+     * <img width="640" height="277" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.s.emitlast.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
@@ -12011,7 +12011,7 @@ public final Observable<T> sample(long period, @NonNull TimeUnit unit, @NonNull
      * emits the most recently emitted item (if any) emitted by the current {@code Observable} since the previous
      * emission from the {@code sampler} {@code ObservableSource}.
      * <p>
-     * <img width="640" height="289" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.nolast.png" alt="">
+     * <img width="640" height="290" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.nolast.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code sample} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -12038,7 +12038,7 @@ public final <U> Observable<T> sample(@NonNull ObservableSource<U> sampler) {
      * emission from the {@code sampler} {@code ObservableSource}
      * and optionally emit the very last upstream item when the upstream or other {@code ObservableSource} complete.
      * <p>
-     * <img width="640" height="289" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.emitlast.png" alt="">
+     * <img width="640" height="290" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.emitlast.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code sample} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -12283,7 +12283,7 @@ public final Single<T> single(@NonNull T defaultItem) {
      * if the current {@code Observable} completes without emitting any items or emits more than one item a
      * {@link NoSuchElementException} or {@link IllegalArgumentException} will be signaled respectively.
      * <p>
-     * <img width="640" height="228" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/singleOrError.png" alt="">
+     * <img width="640" height="206" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/singleOrError.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code singleOrError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -12708,7 +12708,7 @@ public final Observable<T> startWithIterable(@NonNull Iterable<@NonNull ? extend
      * Returns an {@code Observable} which first runs the other {@link CompletableSource}
      * then the current {@code Observable} if the other completed normally.
      * <p>
-     * <img width="640" height="437" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.startWith.c.png" alt="">
+     * <img width="640" height="268" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.startWith.c.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code startWith} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -13052,7 +13052,7 @@ public final Observable<T> subscribeOn(@NonNull Scheduler scheduler) {
      * Returns an {@code Observable} that emits the items emitted by the current {@code Observable} or the items of an alternate
      * {@link ObservableSource} if the current {@code Observable} is empty.
      * <p>
-     * <img width="640" height="255" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.png" alt="">
+     * <img width="640" height="256" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchIfEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -13150,7 +13150,7 @@ public final <R> Observable<R> switchMap(@NonNull Function<? super T, ? extends
      * disposing the subscription to the previous {@code CompletableSource}, thus keeping at most one
      * active {@code CompletableSource} running.
      * <p>
-     * <img width="640" height="521" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapCompletable.f.png" alt="">
+     * <img width="640" height="522" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapCompletable.f.png" alt="">
      * <p>
      * Since a {@code CompletableSource} doesn't produce any items, the resulting reactive type of
      * this operator is a {@link Completable} that can only indicate successful completion or
@@ -13238,7 +13238,7 @@ public final Completable switchMapCompletableDelayError(@NonNull Function<? supe
      * available while failing immediately if the current {@code Observable} or any of the
      * active inner {@code MaybeSource}s fail.
      * <p>
-     * <img width="640" height="350" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMap.o.png" alt="">
+     * <img width="640" height="531" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapMaybe.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchMapMaybe} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -13275,7 +13275,7 @@ public final <R> Observable<R> switchMapMaybe(@NonNull Function<? super T, ? ext
      * while disposing the older ones  (and ignoring their signals) and emits the latest success value of the current one if
      * available, delaying errors from the current {@code Observable} or the inner {@code MaybeSource}s until all terminate.
      * <p>
-     * <img width="640" height="350" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMap.png" alt="">
+     * <img width="640" height="469" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapMaybeDelayError.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchMapMaybeDelayError} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -13306,7 +13306,7 @@ public final <R> Observable<R> switchMapMaybeDelayError(@NonNull Function<? supe
      * The resulting {@code Observable} completes if both the current {@code Observable} and the last inner {@code SingleSource}, if any, complete.
      * If the current {@code Observable} signals an {@code onError}, the inner {@code SingleSource} is disposed and the error delivered in-sequence.
      * <p>
-     * <img width="640" height="531" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapSingle.o.png" alt="">
+     * <img width="640" height="532" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchMapSingle.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -14030,7 +14030,7 @@ public final Observable<T> throttleLast(long intervalDuration, @NonNull TimeUnit
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.png" alt="">
      * <p>
      * Unlike the option with {@link #throttleLatest(long, TimeUnit, boolean)}, the very last item being held back
      * (if any) is not emitted when the upstream completes.
@@ -14063,7 +14063,7 @@ public final Observable<T> throttleLatest(long timeout, @NonNull TimeUnit unit)
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.e.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.e.png" alt="">
      * <p>
      * If no items were emitted from the upstream during this timeout phase, the next
      * upstream item is emitted immediately and the timeout window starts from then.
@@ -14096,7 +14096,7 @@ public final Observable<T> throttleLatest(long timeout, @NonNull TimeUnit unit,
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.s.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.s.png" alt="">
      * <p>
      * Unlike the option with {@link #throttleLatest(long, TimeUnit, Scheduler, boolean)}, the very last item being held back
      * (if any) is not emitted when the upstream completes.
@@ -14130,7 +14130,7 @@ public final Observable<T> throttleLatest(long timeout, @NonNull TimeUnit unit,
      * item from upstream, then periodically emitting the latest item (if any) when
      * the specified timeout elapses between them.
      * <p>
-     * <img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.se.png" alt="">
+     * <img width="640" height="326" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/throttleLatest.se.png" alt="">
      * <p>
      * If no items were emitted from the upstream during this timeout phase, the next
      * upstream item is emitted immediately and the timeout window starts from then.
@@ -15085,7 +15085,7 @@ public final <K, V> Single<Map<K, V>> toMap(
      * </li>
      * <li>{@link BackpressureStrategy#LATEST}
      * <p>
-     * <img width="640" height="296" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/toFlowable.o.latest.png" alt="">
+     * <img width="640" height="297" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/toFlowable.o.latest.png" alt="">
      * </li>
      * <li>{@link BackpressureStrategy#ERROR}
      * <p>
@@ -15093,7 +15093,7 @@ public final <K, V> Single<Map<K, V>> toMap(
      * </li>
      * <li>{@link BackpressureStrategy#MISSING}
      * <p>
-     * <img width="640" height="411" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/toFlowable.o.missing.png" alt="">
+     * <img width="640" height="412" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/toFlowable.o.missing.png" alt="">
      * </li>
      * </ul>
      * <dl>
@@ -15259,7 +15259,7 @@ public final Flowable<T> toFlowable(@NonNull BackpressureStrategy strategy) {
      * Return an {@code Observable} that schedules the downstream {@link Observer}s' {@code dispose} calls
      * aimed at the current {@code Observable} on the given {@link Scheduler}.
      * <p>
-     * <img width="640" height="452" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/unsubscribeOn.o.png" alt="">
+     * <img width="640" height="453" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/unsubscribeOn.o.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 7db69e5bc5..cab4d3c073 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -119,7 +119,7 @@ public abstract class Single<@NonNull T> implements SingleSource<T> {
      * Runs multiple {@link SingleSource}s and signals the events of the first one that signals (disposing
      * the rest).
      * <p>
-     * <img width="640" height="515" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.amb.png" alt="">
+     * <img width="640" height="516" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.amb.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code amb} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -143,7 +143,7 @@ public static <T> Single<T> amb(@NonNull Iterable<@NonNull ? extends SingleSourc
      * Runs multiple {@link SingleSource}s and signals the events of the first one that signals (disposing
      * the rest).
      * <p>
-     * <img width="640" height="515" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.ambArray.png" alt="">
+     * <img width="640" height="516" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.ambArray.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code ambArray} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -224,7 +224,7 @@ public static <T> Observable<T> concat(@NonNull ObservableSource<? extends Singl
      * Concatenate the single values, in a non-overlapping fashion, of the {@link SingleSource}s provided by
      * a {@link Publisher} sequence.
      * <p>
-     * <img width="640" height="308" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.p.png" alt="">
+     * <img width="640" height="309" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.p.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@link Flowable} honors the backpressure of the downstream consumer
@@ -1707,7 +1707,7 @@ public static <T> Flowable<T> switchOnNext(@NonNull Publisher<@NonNull ? extends
      * exposing the success items as a {@link Flowable} sequence and delaying all errors from
      * all of them until all terminate.
      * <p>
-     * <img width="640" height="425" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchOnNextDelayError.png" alt="">
+     * <img width="640" height="423" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchOnNextDelayError.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The {@code sources} {@code Publisher} is consumed in an unbounded manner (requesting {@link Long#MAX_VALUE}).
@@ -1907,7 +1907,7 @@ public static <T, R> Single<R> zip(@NonNull Iterable<@NonNull ? extends SingleSo
      * Returns a {@code Single} that emits the results of a specified combiner function applied to two items emitted by
      * two other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1944,7 +1944,7 @@ public static <T1, T2, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to three items emitted
      * by three other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1986,7 +1986,7 @@ public static <T1, T2, T3, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to four items
      * emitted by four other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2032,7 +2032,7 @@ public static <T1, T2, T3, T4, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to five items
      * emitted by five other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2084,7 +2084,7 @@ public static <T1, T2, T3, T4, T5, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to six items
      * emitted by six other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2140,7 +2140,7 @@ public static <T1, T2, T3, T4, T5, T6, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to seven items
      * emitted by seven other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2201,7 +2201,7 @@ public static <T1, T2, T3, T4, T5, T6, T7, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to eight items
      * emitted by eight other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2266,7 +2266,7 @@ public static <T1, T2, T3, T4, T5, T6, T7, T8, R> Single<R> zip(
      * Returns a {@code Single} that emits the results of a specified combiner function applied to nine items
      * emitted by nine other {@link SingleSource}s.
      * <p>
-     * <img width="640" height="414" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.n.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2895,7 +2895,7 @@ public final Single<T> delaySubscription(long time, @NonNull TimeUnit unit, @Non
     /**
      * Calls the specified consumer with the success item after this item has been emitted to the downstream.
      * <p>
-     * <img width="640" height="460" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.doAfterSuccess.png" alt="">
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.doAfterSuccess.png" alt="">
      * <p>
      * Note that the {@code doAfterSuccess} action is shared between subscriptions and as such
      * should be thread-safe.
@@ -2920,7 +2920,7 @@ public final Single<T> doAfterSuccess(@NonNull Consumer<? super T> onAfterSucces
     /**
      * Registers an {@link Action} to be called after this {@code Single} invokes either {@code onSuccess} or {@code onError}.
      * <p>
-     * <img width="640" height="460" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.doAfterTerminate.png" alt="">
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.doAfterTerminate.png" alt="">
      * <p>
      * Note that the {@code doAfterTerminate} action is shared between subscriptions and as such
      * should be thread-safe.</p>
@@ -3314,7 +3314,7 @@ public final <U> Flowable<U> flattenAsFlowable(@NonNull Function<? super T, ? ex
      * Returns an {@link Observable} that is based on applying a specified function to the item emitted by the current {@code Single},
      * where that function returns an {@link ObservableSource}.
      * <p>
-     * <img width="640" height="300" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMapObservable.png" alt="">
+     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMapObservable.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapObservable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3687,7 +3687,7 @@ public final Single<Notification<T>> materialize() {
      * Signals {@code true} if the current {@code Single} signals a success value that is {@link Object#equals(Object)} with the value
      * provided.
      * <p>
-     * <img width="640" height="400" src="https://raw.githubusercontent.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.contains.png" alt="">
+     * <img width="640" height="401" src="https://raw.githubusercontent.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.contains.png" alt="">
      * <p>
      * <img width="640" height="401" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.contains.png" alt="">
      * <dl>
@@ -3734,7 +3734,7 @@ public final Single<Boolean> contains(@NonNull Object item, @NonNull BiPredicate
     /**
      * Flattens this {@code Single} and another {@link SingleSource} into one {@link Flowable}, without any transformation.
      * <p>
-     * <img width="640" height="415" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.mergeWith.png" alt="">
+     * <img width="640" height="416" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.mergeWith.png" alt="">
      * <p>
      * You can combine items emitted by multiple {@code SingleSource}s so that they appear as one {@code Flowable}, by using
      * the {@code mergeWith} method.
@@ -3814,7 +3814,7 @@ public final Single<T> observeOn(@NonNull Scheduler scheduler) {
      * Ends the flow with a success item returned by a function for the {@link Throwable} error signaled by the current
      * {@code Single} instead of signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorReturn.png" alt="">
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorReturn.png" alt="">
      * <p>
      * By default, when a {@code Single} encounters an error that prevents it from emitting the expected item to its
      * subscriber, the {@code Single} invokes its subscriber's {@link SingleObserver#onError} method, and then quits
@@ -3848,7 +3848,7 @@ public final Single<T> onErrorReturn(@NonNull Function<Throwable, ? extends T> i
     /**
      * Signals the specified value as success in case the current {@code Single} signals an error.
      * <p>
-     * <img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorReturnItem.png" alt="">
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorReturnItem.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code onErrorReturnItem} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3870,7 +3870,7 @@ public final Single<T> onErrorReturnItem(@NonNull T item) {
      * Resumes the flow with the given {@link SingleSource} when the current {@code Single} fails instead of
      * signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorResumeWith.png" alt="">
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorResumeWith.png" alt="">
      * <p>
      * By default, when a {@code Single} encounters an error that prevents it from emitting the expected item to
      * its {@link SingleObserver}, the {@code Single} invokes its {@code SingleObserver}'s {@code onError} method, and then quits
@@ -3925,7 +3925,7 @@ public final Maybe<T> onErrorComplete() {
      * Returns a {@link Maybe} instance that if this {@code Single} emits an error and the predicate returns
      * {@code true}, it will emit an {@code onComplete} and swallow the throwable.
      * <p>
-     * <img width="640" height="220" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorComplete.f.png" alt="">
+     * <img width="640" height="270" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorComplete.f.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code onErrorComplete} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3949,7 +3949,7 @@ public final Maybe<T> onErrorComplete(@NonNull Predicate<? super Throwable> pred
      * Resumes the flow with a {@link SingleSource} returned for the failure {@link Throwable} of the current {@code Single} by a
      * function instead of signaling the error via {@code onError}.
      * <p>
-     * <img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorResumeNext.f.png" alt="">
+     * <img width="640" height="461" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorResumeNext.f.png" alt="">
      * <p>
      * By default, when a {@code Single} encounters an error that prevents it from emitting the expected item to
      * its {@link SingleObserver}, the {@code Single} invokes its {@code SingleObserver}'s {@code onError} method, and then quits
@@ -4007,7 +4007,7 @@ public final Single<T> onTerminateDetach() {
     /**
      * Repeatedly re-subscribes to the current {@code Single} and emits each success value as a {@link Flowable} sequence.
      * <p>
-     * <img width="640" height="457" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.repeat.png" alt="">
+     * <img width="640" height="463" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.repeat.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
@@ -4028,7 +4028,7 @@ public final Flowable<T> repeat() {
     /**
      * Re-subscribes to the current {@code Single} at most the given number of times and emits each success value as a {@link Flowable} sequence.
      * <p>
-     * <img width="640" height="457" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.repeat.n.png" alt="">
+     * <img width="640" height="463" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.repeat.n.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
@@ -4053,7 +4053,7 @@ public final Flowable<T> repeat(long times) {
      * the {@link Publisher} returned by the handler function signals a value in response to a
      * value signaled through the {@link Flowable} the handler receives.
      * <p>
-     * <img width="640" height="1478" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.repeatWhen.png" alt="">
+     * <img width="640" height="1480" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.repeatWhen.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.
@@ -4946,7 +4946,7 @@ public final <E> Single<T> takeUntil(@NonNull SingleSource<? extends E> other) {
      * Signals a {@link TimeoutException} if the current {@code Single} doesn't signal a success value within the
      * specified timeout window.
      * <p>
-     * <img width="640" height="364" src="https://raw.githubusercontent.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeout.png" alt="">
+     * <img width="640" height="334" src="https://raw.githubusercontent.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeout.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code timeout} signals the {@code TimeoutException} on the {@code computation} {@link Scheduler}.</dd>
@@ -5423,7 +5423,7 @@ public final <R> Flowable<R> flattenStreamAsFlowable(@NonNull Function<? super T
      * Maps the upstream succecss value into a Java {@link Stream} and emits its
      * items to the downstream consumer as an {@link Observable}.
      * <p>
-     * <img width="640" height="247" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flattenStreamAsObservable.s.png" alt="">
+     * <img width="640" height="241" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flattenStreamAsObservable.s.png" alt="">
      * <p>
      * The operator closes the {@code Stream} upon cancellation and when it terminates. The exceptions raised when
      * closing a {@code Stream} are routed to the global error handler ({@link RxJavaPlugins#onError(Throwable)}.
diff --git a/src/main/java/io/reactivex/rxjava3/parallel/ParallelFlowable.java b/src/main/java/io/reactivex/rxjava3/parallel/ParallelFlowable.java
index 403f69b1a0..58152e2400 100644
--- a/src/main/java/io/reactivex/rxjava3/parallel/ParallelFlowable.java
+++ b/src/main/java/io/reactivex/rxjava3/parallel/ParallelFlowable.java
@@ -1394,7 +1394,7 @@ public final <R> ParallelFlowable<R> concatMapDelayError(
      * Returns a {@code ParallelFlowable} that merges each item emitted by the source on each rail with the values in an
      * {@link Iterable} corresponding to that item that is generated by a selector.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
+     * <img width="640" height="342" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from each downstream rail. The source {@code ParallelFlowable}s is
@@ -1427,7 +1427,7 @@ public final <U> ParallelFlowable<U> flatMapIterable(@NonNull Function<? super T
      * Returns a {@code ParallelFlowable} that merges each item emitted by the source {@code ParallelFlowable} with the values in an
      * {@link Iterable} corresponding to that item that is generated by a selector.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
+     * <img width="640" height="342" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/flatMapIterable.f.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from each downstream rail. The source {@code ParallelFlowable}s is
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java b/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java
new file mode 100644
index 0000000000..5c0886ea9d
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java
@@ -0,0 +1,106 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+package io.reactivex.rxjava3.internal.util;
+
+import java.awt.image.BufferedImage;
+import java.io.*;
+import java.net.URL;
+import java.nio.file.Files;
+import java.util.*;
+import java.util.regex.*;
+
+import javax.imageio.ImageIO;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.core.Observable;
+import io.reactivex.rxjava3.parallel.ParallelFlowable;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+/**
+ * Parses the main sources, locates the {@code <img>} tags, downloads
+ * the referenced image and checks if the scaled dimensions are correct.
+ */
+public final class MarbleDimensions {
+
+    /** Helper program. */
+    private MarbleDimensions() {
+        throw new IllegalStateException("No instances!");
+    }
+
+    public static void main(String[] args) throws Throwable {
+        Pattern p = Pattern.compile("\\s*\\*\\s*\\<img\\s+width\\=('|\")(\\d+)('|\")\\s+height\\=('|\")(\\d+)('|\")\\s+src\\=('|\")(.+?)('|\").*");
+
+        Map<String, Integer[]> dimensions = new HashMap<>();
+
+        for (Class<?> clazz : CLASSES) {
+            String simpleName = clazz.getSimpleName();
+            System.out.println(simpleName);
+            System.out.println("----");
+            String packageName = clazz.getPackage().getName();
+
+            File f = TestHelper.findSource(clazz.getSimpleName(), packageName);
+            if (f == null) {
+                System.err.println("Unable to locate " + clazz);
+                continue;
+            }
+
+            List<String> lines = Files.readAllLines(f.toPath());
+
+            for (int i = 0; i < lines.size(); i++) {
+                Matcher m = p.matcher(lines.get(i));
+                if (m.matches()) {
+                    int width = Integer.parseInt(m.group(2));
+                    int height = Integer.parseInt(m.group(5));
+                    String url = m.group(8);
+
+                    Integer[] imageDim = dimensions.get(url);
+                    if (imageDim == null) {
+                        Thread.sleep(SLEEP_PER_IMAGE_MILLIS);
+
+                        try {
+                            BufferedImage bimg = ImageIO.read(new URL(url));
+
+                            if (bimg == null) {
+                                throw new IOException("not found");
+                            }
+                            imageDim = new Integer[] { 0, 0 };
+                            imageDim[0] = bimg.getWidth();
+                            imageDim[1] = bimg.getHeight();
+
+                            dimensions.put(url, imageDim);
+                        } catch (IOException ex) {
+                            System.err.printf("%s => %s%n", url, ex);
+                            System.err.printf(" at %s.%s.method(%s.java:%d)%n", packageName, simpleName, simpleName, i + 1);
+                        }
+                    }
+
+                    if (imageDim != null) {
+                        int expectedHeight = (int)Math.round(1.0 * width / imageDim[0] * imageDim[1]);
+
+                        if (expectedHeight != height) {
+                            System.out.printf("    %d => %d%n", height, expectedHeight);
+                            System.out.printf(" at %s.%s.method(%s.java:%d)%n", packageName, simpleName, simpleName, i + 1);
+                        }
+                    }
+                    // System.out.printf("%d: %d x %d => %s%n", i + 1, width, height, url);
+                }
+            }
+        }
+    }
+
+    static final int SLEEP_PER_IMAGE_MILLIS = 100;
+
+    static final Class<?>[] CLASSES = {
+            Flowable.class, Observable.class, Maybe.class, Single.class, Completable.class, ParallelFlowable.class
+    };
+}

From f1a795da0d4cdfb3133206ad8e3887bdb8ba948b Mon Sep 17 00:00:00 2001
From: slisaasquatch <slisaasquatch@users.noreply.github.com>
Date: Tue, 28 Jan 2020 12:32:19 -0800
Subject: [PATCH 33/37] 3.x: Swap Maybe.flatMapSingle and
 Maybe.flatMapSingleElement (#6891)

* Deleted Maybe.flatMapSingle

And replaced tests with flatMapSingle().toSingle()

* Renamed Maybe.flatMapSingleElement to flatMapSingle

* Deleted unused MaybeFlatMapSingle operator

* Renamed operator MaybeFlatMapSingleElement to MaybeFlatMapSingle

* Add Ignore to XFlatMapTest.maybeSingle
---
 .../java/io/reactivex/rxjava3/core/Maybe.java |  37 +----
 .../operators/maybe/MaybeFlatMapSingle.java   |  21 ++-
 .../maybe/MaybeFlatMapSingleElement.java      | 132 ------------------
 .../reactivex/rxjava3/core/XFlatMapTest.java  |   2 +
 .../maybe/MaybeFlatMapSingleElementTest.java  |  30 ++--
 .../maybe/MaybeFlatMapSingleTest.java         |  11 +-
 6 files changed, 41 insertions(+), 192 deletions(-)
 delete mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElement.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 37ce1e99e2..f8cbdcdbe7 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -2932,7 +2932,7 @@ public final Completable concatMapCompletable(@NonNull Function<? super T, ? ext
      * <p>
      * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatMapSingle.png" alt="">
      * <p>
-     * This operator is an alias for {@link #flatMapSingleElement(Function)}.
+     * This operator is an alias for {@link #flatMapSingle(Function)}.
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code concatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2951,7 +2951,7 @@ public final Completable concatMapCompletable(@NonNull Function<? super T, ? ext
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public final <R> Maybe<R> concatMapSingle(@NonNull Function<? super T, ? extends SingleSource<? extends R>> mapper) {
-        return flatMapSingleElement(mapper);
+        return flatMapSingle(mapper);
     }
 
     /**
@@ -3832,33 +3832,6 @@ public final <R> Flowable<R> flatMapPublisher(@NonNull Function<? super T, ? ext
         return RxJavaPlugins.onAssembly(new MaybeFlatMapPublisher<>(this, mapper));
     }
 
-    /**
-     * Returns a {@link Single} based on applying a specified function to the item emitted by the
-     * current {@code Maybe}, where that function returns a {@code Single}.
-     * When this {@code Maybe} completes a {@link NoSuchElementException} will be thrown.
-     * <p>
-     * <img width="640" height="346" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle3.png" alt="">
-     * <dl>
-     * <dt><b>Scheduler:</b></dt>
-     * <dd>{@code flatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
-     * </dl>
-     *
-     * @param <R> the result value type
-     * @param mapper
-     *            a function that, when applied to the item emitted by the current {@code Maybe}, returns a
-     *            {@code Single}
-     * @return the new {@code Single} instance
-     * @throws NullPointerException if {@code mapper} is {@code null}
-     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
-     */
-    @CheckReturnValue
-    @NonNull
-    @SchedulerSupport(SchedulerSupport.NONE)
-    public final <R> Single<R> flatMapSingle(@NonNull Function<? super T, ? extends SingleSource<? extends R>> mapper) {
-        Objects.requireNonNull(mapper, "mapper is null");
-        return RxJavaPlugins.onAssembly(new MaybeFlatMapSingle<>(this, mapper));
-    }
-
     /**
      * Returns a {@code Maybe} based on applying a specified function to the item emitted by the
      * current {@code Maybe}, where that function returns a {@link Single}.
@@ -3867,7 +3840,7 @@ public final <R> Single<R> flatMapSingle(@NonNull Function<? super T, ? extends
      * <img width="640" height="357" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapSingle.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
-     * <dd>{@code flatMapSingleElement} does not operate by default on a particular {@link Scheduler}.</dd>
+     * <dd>{@code flatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      *
      * <p>History: 2.0.2 - experimental
@@ -3883,9 +3856,9 @@ public final <R> Single<R> flatMapSingle(@NonNull Function<? super T, ? extends
     @CheckReturnValue
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
-    public final <R> Maybe<R> flatMapSingleElement(@NonNull Function<? super T, ? extends SingleSource<? extends R>> mapper) {
+    public final <R> Maybe<R> flatMapSingle(@NonNull Function<? super T, ? extends SingleSource<? extends R>> mapper) {
         Objects.requireNonNull(mapper, "mapper is null");
-        return RxJavaPlugins.onAssembly(new MaybeFlatMapSingleElement<>(this, mapper));
+        return RxJavaPlugins.onAssembly(new MaybeFlatMapSingle<>(this, mapper));
     }
 
     /**
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java
index 2199ea470b..aed71dc855 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java
@@ -13,7 +13,6 @@
 
 package io.reactivex.rxjava3.internal.operators.maybe;
 
-import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -25,10 +24,12 @@
 
 /**
  * Maps the success value of the source MaybeSource into a Single.
+ * <p>History: 2.0.2 - experimental
  * @param <T> the input value type
  * @param <R> the result value type
+ * @since 2.1
  */
-public final class MaybeFlatMapSingle<T, R> extends Single<R> {
+public final class MaybeFlatMapSingle<T, R> extends Maybe<R> {
 
     final MaybeSource<T> source;
 
@@ -40,7 +41,7 @@ public MaybeFlatMapSingle(MaybeSource<T> source, Function<? super T, ? extends S
     }
 
     @Override
-    protected void subscribeActual(SingleObserver<? super R> downstream) {
+    protected void subscribeActual(MaybeObserver<? super R> downstream) {
         source.subscribe(new FlatMapMaybeObserver<>(downstream, mapper));
     }
 
@@ -50,11 +51,11 @@ static final class FlatMapMaybeObserver<T, R>
 
         private static final long serialVersionUID = 4827726964688405508L;
 
-        final SingleObserver<? super R> downstream;
+        final MaybeObserver<? super R> downstream;
 
         final Function<? super T, ? extends SingleSource<? extends R>> mapper;
 
-        FlatMapMaybeObserver(SingleObserver<? super R> actual, Function<? super T, ? extends SingleSource<? extends R>> mapper) {
+        FlatMapMaybeObserver(MaybeObserver<? super R> actual, Function<? super T, ? extends SingleSource<? extends R>> mapper) {
             this.downstream = actual;
             this.mapper = mapper;
         }
@@ -88,9 +89,7 @@ public void onSuccess(T value) {
                 return;
             }
 
-            if (!isDisposed()) {
-                ss.subscribe(new FlatMapSingleObserver<R>(this, downstream));
-            }
+            ss.subscribe(new FlatMapSingleObserver<R>(this, downstream));
         }
 
         @Override
@@ -100,7 +99,7 @@ public void onError(Throwable e) {
 
         @Override
         public void onComplete() {
-            downstream.onError(new NoSuchElementException());
+            downstream.onComplete();
         }
     }
 
@@ -108,9 +107,9 @@ static final class FlatMapSingleObserver<R> implements SingleObserver<R> {
 
         final AtomicReference<Disposable> parent;
 
-        final SingleObserver<? super R> downstream;
+        final MaybeObserver<? super R> downstream;
 
-        FlatMapSingleObserver(AtomicReference<Disposable> parent, SingleObserver<? super R> downstream) {
+        FlatMapSingleObserver(AtomicReference<Disposable> parent, MaybeObserver<? super R> downstream) {
             this.parent = parent;
             this.downstream = downstream;
         }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElement.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElement.java
deleted file mode 100644
index 49b7100575..0000000000
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElement.java
+++ /dev/null
@@ -1,132 +0,0 @@
-/**
- * Copyright (c) 2016-present, RxJava Contributors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
- * compliance with the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software distributed under the License is
- * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
- * the License for the specific language governing permissions and limitations under the License.
- */
-
-package io.reactivex.rxjava3.internal.operators.maybe;
-
-import java.util.Objects;
-import java.util.concurrent.atomic.AtomicReference;
-
-import io.reactivex.rxjava3.core.*;
-import io.reactivex.rxjava3.disposables.Disposable;
-import io.reactivex.rxjava3.exceptions.Exceptions;
-import io.reactivex.rxjava3.functions.Function;
-import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
-
-/**
- * Maps the success value of the source MaybeSource into a Single.
- * <p>History: 2.0.2 - experimental
- * @param <T> the input value type
- * @param <R> the result value type
- * @since 2.1
- */
-public final class MaybeFlatMapSingleElement<T, R> extends Maybe<R> {
-
-    final MaybeSource<T> source;
-
-    final Function<? super T, ? extends SingleSource<? extends R>> mapper;
-
-    public MaybeFlatMapSingleElement(MaybeSource<T> source, Function<? super T, ? extends SingleSource<? extends R>> mapper) {
-        this.source = source;
-        this.mapper = mapper;
-    }
-
-    @Override
-    protected void subscribeActual(MaybeObserver<? super R> downstream) {
-        source.subscribe(new FlatMapMaybeObserver<>(downstream, mapper));
-    }
-
-    static final class FlatMapMaybeObserver<T, R>
-    extends AtomicReference<Disposable>
-    implements MaybeObserver<T>, Disposable {
-
-        private static final long serialVersionUID = 4827726964688405508L;
-
-        final MaybeObserver<? super R> downstream;
-
-        final Function<? super T, ? extends SingleSource<? extends R>> mapper;
-
-        FlatMapMaybeObserver(MaybeObserver<? super R> actual, Function<? super T, ? extends SingleSource<? extends R>> mapper) {
-            this.downstream = actual;
-            this.mapper = mapper;
-        }
-
-        @Override
-        public void dispose() {
-            DisposableHelper.dispose(this);
-        }
-
-        @Override
-        public boolean isDisposed() {
-            return DisposableHelper.isDisposed(get());
-        }
-
-        @Override
-        public void onSubscribe(Disposable d) {
-            if (DisposableHelper.setOnce(this, d)) {
-                downstream.onSubscribe(this);
-            }
-        }
-
-        @Override
-        public void onSuccess(T value) {
-            SingleSource<? extends R> ss;
-
-            try {
-                ss = Objects.requireNonNull(mapper.apply(value), "The mapper returned a null SingleSource");
-            } catch (Throwable ex) {
-                Exceptions.throwIfFatal(ex);
-                onError(ex);
-                return;
-            }
-
-            ss.subscribe(new FlatMapSingleObserver<R>(this, downstream));
-        }
-
-        @Override
-        public void onError(Throwable e) {
-            downstream.onError(e);
-        }
-
-        @Override
-        public void onComplete() {
-            downstream.onComplete();
-        }
-    }
-
-    static final class FlatMapSingleObserver<R> implements SingleObserver<R> {
-
-        final AtomicReference<Disposable> parent;
-
-        final MaybeObserver<? super R> downstream;
-
-        FlatMapSingleObserver(AtomicReference<Disposable> parent, MaybeObserver<? super R> downstream) {
-            this.parent = parent;
-            this.downstream = downstream;
-        }
-
-        @Override
-        public void onSubscribe(final Disposable d) {
-            DisposableHelper.replace(parent, d);
-        }
-
-        @Override
-        public void onSuccess(final R value) {
-            downstream.onSuccess(value);
-        }
-
-        @Override
-        public void onError(final Throwable e) {
-            downstream.onError(e);
-        }
-    }
-}
diff --git a/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java b/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java
index 7efeee401d..6e80b57904 100644
--- a/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java
+++ b/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java
@@ -505,6 +505,7 @@ public Completable apply(Integer v) throws Exception {
     }
 
     @Test
+    @Ignore
     public void maybeSingle() throws Exception {
         List<Throwable> errors = TestHelper.trackPluginErrors();
         try {
@@ -517,6 +518,7 @@ public Single<Integer> apply(Integer v) throws Exception {
                     return Single.<Integer>error(new TestException());
                 }
             })
+            .toSingle()
             .test();
 
             cb.await();
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElementTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElementTest.java
index 3d85785add..cc92e023ab 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElementTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleElementTest.java
@@ -22,8 +22,8 @@
 
 public class MaybeFlatMapSingleElementTest extends RxJavaTest {
     @Test
-    public void flatMapSingleElementValue() {
-        Maybe.just(1).flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+    public void flatMapSingleValue() {
+        Maybe.just(1).flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
             @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
                 if (integer == 1) {
                     return Single.just(2);
@@ -37,8 +37,8 @@ public void flatMapSingleElementValue() {
     }
 
     @Test
-    public void flatMapSingleElementValueDifferentType() {
-        Maybe.just(1).flatMapSingleElement(new Function<Integer, SingleSource<String>>() {
+    public void flatMapSingleValueDifferentType() {
+        Maybe.just(1).flatMapSingle(new Function<Integer, SingleSource<String>>() {
             @Override public SingleSource<String> apply(final Integer integer) throws Exception {
                 if (integer == 1) {
                     return Single.just("2");
@@ -52,8 +52,8 @@ public void flatMapSingleElementValueDifferentType() {
     }
 
     @Test
-    public void flatMapSingleElementValueNull() {
-        Maybe.just(1).flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+    public void flatMapSingleValueNull() {
+        Maybe.just(1).flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
             @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
                 return null;
             }
@@ -65,8 +65,8 @@ public void flatMapSingleElementValueNull() {
     }
 
     @Test
-    public void flatMapSingleElementValueErrorThrown() {
-        Maybe.just(1).flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+    public void flatMapSingleValueErrorThrown() {
+        Maybe.just(1).flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
             @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
                 throw new RuntimeException("something went terribly wrong!");
             }
@@ -78,10 +78,10 @@ public void flatMapSingleElementValueErrorThrown() {
     }
 
     @Test
-    public void flatMapSingleElementError() {
+    public void flatMapSingleError() {
         RuntimeException exception = new RuntimeException("test");
 
-        Maybe.error(exception).flatMapSingleElement(new Function<Object, SingleSource<Object>>() {
+        Maybe.error(exception).flatMapSingle(new Function<Object, SingleSource<Object>>() {
             @Override public SingleSource<Object> apply(final Object integer) throws Exception {
                 return Single.just(new Object());
             }
@@ -91,8 +91,8 @@ public void flatMapSingleElementError() {
     }
 
     @Test
-    public void flatMapSingleElementEmpty() {
-        Maybe.<Integer>empty().flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+    public void flatMapSingleEmpty() {
+        Maybe.<Integer>empty().flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
             @Override public SingleSource<Integer> apply(final Integer integer) throws Exception {
                 return Single.just(2);
             }
@@ -104,7 +104,7 @@ public void flatMapSingleElementEmpty() {
 
     @Test
     public void dispose() {
-        TestHelper.checkDisposed(Maybe.just(1).flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+        TestHelper.checkDisposed(Maybe.just(1).flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
             @Override
             public SingleSource<Integer> apply(final Integer integer) throws Exception {
                 return Single.just(2);
@@ -117,7 +117,7 @@ public void doubleOnSubscribe() {
         TestHelper.checkDoubleOnSubscribeMaybe(new Function<Maybe<Integer>, Maybe<Integer>>() {
             @Override
             public Maybe<Integer> apply(Maybe<Integer> m) throws Exception {
-                return m.flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+                return m.flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
                     @Override
                     public SingleSource<Integer> apply(final Integer integer) throws Exception {
                         return Single.just(2);
@@ -130,7 +130,7 @@ public SingleSource<Integer> apply(final Integer integer) throws Exception {
     @Test
     public void singleErrors() {
         Maybe.just(1)
-        .flatMapSingleElement(new Function<Integer, SingleSource<Integer>>() {
+        .flatMapSingle(new Function<Integer, SingleSource<Integer>>() {
                     @Override
                     public SingleSource<Integer> apply(final Integer integer) throws Exception {
                         return Single.error(new TestException());
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleTest.java
index c4cef0d351..4904678a61 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingleTest.java
@@ -34,6 +34,7 @@ public void flatMapSingleValue() {
                 return Single.just(1);
             }
         })
+            .toSingle()
             .test()
             .assertResult(2);
     }
@@ -49,6 +50,7 @@ public void flatMapSingleValueDifferentType() {
                 return Single.just("1");
             }
         })
+            .toSingle()
             .test()
             .assertResult("2");
     }
@@ -60,6 +62,7 @@ public void flatMapSingleValueNull() {
                 return null;
             }
         })
+        .toSingle()
         .to(TestHelper.<Integer>testConsumer())
             .assertNoValues()
             .assertError(NullPointerException.class)
@@ -73,6 +76,7 @@ public void flatMapSingleValueErrorThrown() {
                 throw new RuntimeException("something went terribly wrong!");
             }
         })
+        .toSingle()
         .to(TestHelper.<Integer>testConsumer())
             .assertNoValues()
             .assertError(RuntimeException.class)
@@ -88,6 +92,7 @@ public void flatMapSingleError() {
                 return Single.just(new Object());
             }
         })
+            .toSingle()
             .test()
             .assertError(exception);
     }
@@ -99,6 +104,7 @@ public void flatMapSingleEmpty() {
                 return Single.just(2);
             }
         })
+            .toSingle()
             .test()
             .assertNoValues()
             .assertError(NoSuchElementException.class);
@@ -111,7 +117,7 @@ public void dispose() {
             public SingleSource<Integer> apply(final Integer integer) throws Exception {
                 return Single.just(2);
             }
-        }));
+        }).toSingle());
     }
 
     @Test
@@ -124,7 +130,7 @@ public SingleSource<Integer> apply(Maybe<Integer> m) throws Exception {
                     public SingleSource<Integer> apply(final Integer integer) throws Exception {
                         return Single.just(2);
                     }
-                });
+                }).toSingle();
             }
         });
     }
@@ -138,6 +144,7 @@ public SingleSource<Integer> apply(final Integer integer) throws Exception {
                         return Single.error(new TestException());
                     }
                 })
+        .toSingle()
         .test()
         .assertFailure(TestException.class);
     }

From 5f6aafcbaa97f330ad2007f4ad02c5e33db8914b Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Wed, 29 Jan 2020 11:57:40 +0100
Subject: [PATCH 34/37] 3.x: Fix groupBy not requesting more if a group is
 cancelled w/ items (#6895)

---
 .../operators/flowable/FlowableGroupBy.java   |  1 +
 .../flowable/FlowableGroupByTest.java         | 34 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupBy.java b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupBy.java
index 3cb84d4d6b..9a42e927bc 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupBy.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupBy.java
@@ -401,6 +401,7 @@ public void request(long n) {
         public void cancel() {
             if (cancelled.compareAndSet(false, true)) {
                 cancelParent();
+                drain();
             }
         }
 
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupByTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupByTest.java
index f20f0ae0c7..ddc34f1d98 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupByTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableGroupByTest.java
@@ -2444,4 +2444,38 @@ public void accept(Integer v) throws Throwable {
         .assertNoErrors()
         .assertComplete();
     }
+
+    @Test
+    public void cancelledGroupResumesRequesting() {
+        final List<TestSubscriber<Integer>> tss = new ArrayList<>();
+        final AtomicInteger counter = new AtomicInteger();
+        final AtomicBoolean done = new AtomicBoolean();
+        Flowable.range(1, 1000)
+                .doOnNext(new Consumer<Integer>() {
+                    @Override
+                    public void accept(Integer v) throws Exception {
+                        counter.getAndIncrement();
+                    }
+                })
+                .groupBy(Functions.justFunction(1))
+                .subscribe(new Consumer<GroupedFlowable<Integer, Integer>>() {
+                    @Override
+                    public void accept(GroupedFlowable<Integer, Integer> v) throws Exception {
+                        TestSubscriber<Integer> ts = TestSubscriber.create(0L);
+                        tss.add(ts);
+                        v.subscribe(ts);
+                    }
+                }, Functions.emptyConsumer(), new Action() {
+                    @Override
+                    public void run() throws Exception {
+                        done.set(true);
+                    }
+                });
+
+        while (!done.get()) {
+            tss.remove(0).cancel();
+        }
+
+        assertEquals(1000, counter.get());
+    }
 }

From c181169bf238a841c54e8957055ca31c02fd495d Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Wed, 29 Jan 2020 12:52:12 +0100
Subject: [PATCH 35/37] 3.x: Reenable XFlatMapTest.maybeSingle, add missing
 Single operators (#6893)

---
 .../java/io/reactivex/rxjava3/core/Maybe.java |   4 +-
 .../io/reactivex/rxjava3/core/Single.java     |  66 +++
 .../maybe/MaybeFlatMapNotification.java       |  12 +-
 .../operators/maybe/MaybeFlatMapSingle.java   |   4 +-
 .../mixed/MaybeFlatMapObservable.java         |   4 +-
 .../mixed/MaybeFlatMapPublisher.java          |   4 +-
 .../mixed/SingleFlatMapObservable.java        |   4 +-
 .../single/SingleFlatMapBiSelector.java       | 156 ++++++
 .../single/SingleFlatMapNotification.java     | 147 ++++++
 .../single/SingleFlatMapPublisher.java        |   4 +-
 .../reactivex/rxjava3/core/XFlatMapTest.java  | 443 +++++++++++++++++-
 .../single/SingleFlatMapBiSelectorTest.java   | 205 ++++++++
 .../single/SingleFlatMapNotificationTest.java | 113 +++++
 13 files changed, 1153 insertions(+), 13 deletions(-)
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelector.java
 create mode 100644 src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotification.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelectorTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotificationTest.java

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index f8cbdcdbe7..20e52f2f5f 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -3653,7 +3653,7 @@ public final <R> Maybe<R> flatMap(@NonNull Function<? super T, ? extends MaybeSo
     }
 
     /**
-     * Maps the {@code onSuccess}, {@code onError} or {@code onComplete} signals of this {@code Maybe} into {@link MaybeSource} and emits that
+     * Maps the {@code onSuccess}, {@code onError} or {@code onComplete} signals of the current {@code Maybe} into a {@link MaybeSource} and emits that
      * {@code MaybeSource}'s signals.
      * <p>
      * <img width="640" height="354" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.mmm.png" alt="">
@@ -3691,7 +3691,7 @@ public final <R> Maybe<R> flatMap(
      * Returns a {@code Maybe} that emits the results of a specified function to the pair of values emitted by the
      * current {@code Maybe} and a specified mapped {@link MaybeSource}.
      * <p>
-     * <img width="640" height="390" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/mergeMap.r.png" alt="">
+     * <img width="640" height="268" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.combiner.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index cab4d3c073..667125b08b 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -3196,6 +3196,72 @@ public final <R> Single<R> flatMap(@NonNull Function<? super T, ? extends Single
         return RxJavaPlugins.onAssembly(new SingleFlatMap<>(this, mapper));
     }
 
+    /**
+     * Returns a {@code Single} that emits the results of a specified function to the pair of values emitted by the
+     * current {@code Single} and a specified mapped {@link SingleSource}.
+     * <p>
+     * <img width="640" height="268" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMap.combiner.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <U>
+     *            the type of items emitted by the {@code SingleSource} returned by the {@code mapper} function
+     * @param <R>
+     *            the type of items emitted by the resulting {@code Single}
+     * @param mapper
+     *            a function that returns a {@code SingleSource} for the item emitted by the current {@code Single}
+     * @param combiner
+     *            a function that combines one item emitted by each of the source and collection {@code SingleSource} and
+     *            returns an item to be emitted by the resulting {@code SingleSource}
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code mapper} or {@code combiner} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <U, R> Single<R> flatMap(@NonNull Function<? super T, ? extends SingleSource<? extends U>> mapper,
+            @NonNull BiFunction<? super T, ? super U, ? extends R> combiner) {
+        Objects.requireNonNull(mapper, "mapper is null");
+        Objects.requireNonNull(combiner, "combiner is null");
+        return RxJavaPlugins.onAssembly(new SingleFlatMapBiSelector<>(this, mapper, combiner));
+    }
+
+    /**
+     * Maps the {@code onSuccess} or {@code onError} signals of the current {@code Single} into a {@link SingleSource} and emits that
+     * {@code SingleSource}'s signals.
+     * <p>
+     * <img width="640" height="449" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMap.notification.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param <R>
+     *            the result type
+     * @param onSuccessMapper
+     *            a function that returns a {@code SingleSource} to merge for the {@code onSuccess} item emitted by this {@code Single}
+     * @param onErrorMapper
+     *            a function that returns a {@code SingleSource} to merge for an {@code onError} notification from this {@code Single}
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code onSuccessMapper} or {@code onErrorMapper} is {@code null}
+     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final <R> Single<R> flatMap(
+            @NonNull Function<? super T, ? extends SingleSource<? extends R>> onSuccessMapper,
+            @NonNull Function<? super Throwable, ? extends SingleSource<? extends R>> onErrorMapper) {
+        Objects.requireNonNull(onSuccessMapper, "onSuccessMapper is null");
+        Objects.requireNonNull(onErrorMapper, "onErrorMapper is null");
+        return RxJavaPlugins.onAssembly(new SingleFlatMapNotification<>(this, onSuccessMapper, onErrorMapper));
+    }
+
     /**
      * Returns a {@link Maybe} that is based on applying a specified function to the item emitted by the current {@code Single},
      * where that function returns a {@link MaybeSource}.
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapNotification.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapNotification.java
index e357938db2..ffe6ee5e20 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapNotification.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapNotification.java
@@ -109,7 +109,9 @@ public void onSuccess(T value) {
                 return;
             }
 
-            source.subscribe(new InnerObserver());
+            if (!isDisposed()) {
+                source.subscribe(new InnerObserver());
+            }
         }
 
         @Override
@@ -124,7 +126,9 @@ public void onError(Throwable e) {
                 return;
             }
 
-            source.subscribe(new InnerObserver());
+            if (!isDisposed()) {
+                source.subscribe(new InnerObserver());
+            }
         }
 
         @Override
@@ -139,7 +143,9 @@ public void onComplete() {
                 return;
             }
 
-            source.subscribe(new InnerObserver());
+            if (!isDisposed()) {
+                source.subscribe(new InnerObserver());
+            }
         }
 
         final class InnerObserver implements MaybeObserver<R> {
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java
index aed71dc855..999b22f836 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeFlatMapSingle.java
@@ -89,7 +89,9 @@ public void onSuccess(T value) {
                 return;
             }
 
-            ss.subscribe(new FlatMapSingleObserver<R>(this, downstream));
+            if (!isDisposed()) {
+                ss.subscribe(new FlatMapSingleObserver<R>(this, downstream));
+            }
         }
 
         @Override
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapObservable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapObservable.java
index ae42405f74..ef1dc5f023 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapObservable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapObservable.java
@@ -106,7 +106,9 @@ public void onSuccess(T t) {
                 return;
             }
 
-            o.subscribe(this);
+            if (!isDisposed()) {
+                o.subscribe(this);
+            }
         }
 
     }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapPublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapPublisher.java
index c590755704..82a6d5da7d 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapPublisher.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/MaybeFlatMapPublisher.java
@@ -116,7 +116,9 @@ public void onSuccess(T t) {
                 return;
             }
 
-            p.subscribe(this);
+            if (get() != SubscriptionHelper.CANCELLED) {
+                p.subscribe(this);
+            }
         }
 
         @Override
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/SingleFlatMapObservable.java b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/SingleFlatMapObservable.java
index c3dd9b59c1..b2562d8dba 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/SingleFlatMapObservable.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/mixed/SingleFlatMapObservable.java
@@ -106,7 +106,9 @@ public void onSuccess(T t) {
                 return;
             }
 
-            o.subscribe(this);
+            if (!isDisposed()) {
+                o.subscribe(this);
+            }
         }
 
     }
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelector.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelector.java
new file mode 100644
index 0000000000..d1051f3357
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelector.java
@@ -0,0 +1,156 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.Exceptions;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+
+/**
+ * Maps a source item to another SingleSource then calls a BiFunction with the
+ * original item and the secondary item to generate the final result.
+ *
+ * @param <T> the main value type
+ * @param <U> the second value type
+ * @param <R> the result value type
+ * @since 3.0.0
+ */
+public final class SingleFlatMapBiSelector<T, U, R> extends Single<R> {
+
+    final SingleSource<T> source;
+
+    final Function<? super T, ? extends SingleSource<? extends U>> mapper;
+
+    final BiFunction<? super T, ? super U, ? extends R> resultSelector;
+
+    public SingleFlatMapBiSelector(SingleSource<T> source,
+            Function<? super T, ? extends SingleSource<? extends U>> mapper,
+            BiFunction<? super T, ? super U, ? extends R> resultSelector) {
+        this.source = source;
+        this.mapper = mapper;
+        this.resultSelector = resultSelector;
+    }
+
+    @Override
+    protected void subscribeActual(SingleObserver<? super R> observer) {
+        source.subscribe(new FlatMapBiMainObserver<T, U, R>(observer, mapper, resultSelector));
+    }
+
+    static final class FlatMapBiMainObserver<T, U, R>
+    implements SingleObserver<T>, Disposable {
+
+        final Function<? super T, ? extends SingleSource<? extends U>> mapper;
+
+        final InnerObserver<T, U, R> inner;
+
+        FlatMapBiMainObserver(SingleObserver<? super R> actual,
+                Function<? super T, ? extends SingleSource<? extends U>> mapper,
+                BiFunction<? super T, ? super U, ? extends R> resultSelector) {
+            this.inner = new InnerObserver<>(actual, resultSelector);
+            this.mapper = mapper;
+        }
+
+        @Override
+        public void dispose() {
+            DisposableHelper.dispose(inner);
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return DisposableHelper.isDisposed(inner.get());
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.setOnce(inner, d)) {
+                inner.downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(T value) {
+            SingleSource<? extends U> next;
+
+            try {
+                next = Objects.requireNonNull(mapper.apply(value), "The mapper returned a null MaybeSource");
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                inner.downstream.onError(ex);
+                return;
+            }
+
+            if (DisposableHelper.replace(inner, null)) {
+                inner.value = value;
+                next.subscribe(inner);
+            }
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            inner.downstream.onError(e);
+        }
+
+        static final class InnerObserver<T, U, R>
+        extends AtomicReference<Disposable>
+        implements SingleObserver<U> {
+
+            private static final long serialVersionUID = -2897979525538174559L;
+
+            final SingleObserver<? super R> downstream;
+
+            final BiFunction<? super T, ? super U, ? extends R> resultSelector;
+
+            T value;
+
+            InnerObserver(SingleObserver<? super R> actual,
+                    BiFunction<? super T, ? super U, ? extends R> resultSelector) {
+                this.downstream = actual;
+                this.resultSelector = resultSelector;
+            }
+
+            @Override
+            public void onSubscribe(Disposable d) {
+                DisposableHelper.setOnce(this, d);
+            }
+
+            @Override
+            public void onSuccess(U value) {
+                T t = this.value;
+                this.value = null;
+
+                R r;
+
+                try {
+                    r = Objects.requireNonNull(resultSelector.apply(t, value), "The resultSelector returned a null value");
+                } catch (Throwable ex) {
+                    Exceptions.throwIfFatal(ex);
+                    downstream.onError(ex);
+                    return;
+                }
+
+                downstream.onSuccess(r);
+            }
+
+            @Override
+            public void onError(Throwable e) {
+                downstream.onError(e);
+            }
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotification.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotification.java
new file mode 100644
index 0000000000..1ba9796b7c
--- /dev/null
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotification.java
@@ -0,0 +1,147 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
+
+/**
+ * Maps a value into a SingleSource and relays its signal.
+ *
+ * @param <T> the source value type
+ * @param <R> the result value type
+ * @since 3.0.0
+ */
+public final class SingleFlatMapNotification<T, R> extends Single<R> {
+
+    final SingleSource<T> source;
+
+    final Function<? super T, ? extends SingleSource<? extends R>> onSuccessMapper;
+
+    final Function<? super Throwable, ? extends SingleSource<? extends R>> onErrorMapper;
+
+    public SingleFlatMapNotification(SingleSource<T> source,
+            Function<? super T, ? extends SingleSource<? extends R>> onSuccessMapper,
+            Function<? super Throwable, ? extends SingleSource<? extends R>> onErrorMapper) {
+        this.source = source;
+        this.onSuccessMapper = onSuccessMapper;
+        this.onErrorMapper = onErrorMapper;
+    }
+
+    @Override
+    protected void subscribeActual(SingleObserver<? super R> observer) {
+        source.subscribe(new FlatMapSingleObserver<>(observer, onSuccessMapper, onErrorMapper));
+    }
+
+    static final class FlatMapSingleObserver<T, R>
+    extends AtomicReference<Disposable>
+    implements SingleObserver<T>, Disposable {
+
+        private static final long serialVersionUID = 4375739915521278546L;
+
+        final SingleObserver<? super R> downstream;
+
+        final Function<? super T, ? extends SingleSource<? extends R>> onSuccessMapper;
+
+        final Function<? super Throwable, ? extends SingleSource<? extends R>> onErrorMapper;
+
+        Disposable upstream;
+
+        FlatMapSingleObserver(SingleObserver<? super R> actual,
+                Function<? super T, ? extends SingleSource<? extends R>> onSuccessMapper,
+                Function<? super Throwable, ? extends SingleSource<? extends R>> onErrorMapper) {
+            this.downstream = actual;
+            this.onSuccessMapper = onSuccessMapper;
+            this.onErrorMapper = onErrorMapper;
+        }
+
+        @Override
+        public void dispose() {
+            DisposableHelper.dispose(this);
+            upstream.dispose();
+        }
+
+        @Override
+        public boolean isDisposed() {
+            return DisposableHelper.isDisposed(get());
+        }
+
+        @Override
+        public void onSubscribe(Disposable d) {
+            if (DisposableHelper.validate(this.upstream, d)) {
+                this.upstream = d;
+
+                downstream.onSubscribe(this);
+            }
+        }
+
+        @Override
+        public void onSuccess(T value) {
+            SingleSource<? extends R> source;
+
+            try {
+                source = Objects.requireNonNull(onSuccessMapper.apply(value), "The onSuccessMapper returned a null SingleSource");
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                downstream.onError(ex);
+                return;
+            }
+
+            if (!isDisposed()) {
+                source.subscribe(new InnerObserver());
+            }
+        }
+
+        @Override
+        public void onError(Throwable e) {
+            SingleSource<? extends R> source;
+
+            try {
+                source = Objects.requireNonNull(onErrorMapper.apply(e), "The onErrorMapper returned a null SingleSource");
+            } catch (Throwable ex) {
+                Exceptions.throwIfFatal(ex);
+                downstream.onError(new CompositeException(e, ex));
+                return;
+            }
+
+            if (!isDisposed()) {
+                source.subscribe(new InnerObserver());
+            }
+        }
+
+        final class InnerObserver implements SingleObserver<R> {
+
+            @Override
+            public void onSubscribe(Disposable d) {
+                DisposableHelper.setOnce(FlatMapSingleObserver.this, d);
+            }
+
+            @Override
+            public void onSuccess(R value) {
+                downstream.onSuccess(value);
+            }
+
+            @Override
+            public void onError(Throwable e) {
+                downstream.onError(e);
+            }
+        }
+    }
+}
diff --git a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapPublisher.java b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapPublisher.java
index f474830e40..c89913791d 100644
--- a/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapPublisher.java
+++ b/src/main/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapPublisher.java
@@ -92,7 +92,9 @@ public void onSuccess(S value) {
                 downstream.onError(e);
                 return;
             }
-            f.subscribe(this);
+            if (parent.get() != SubscriptionHelper.CANCELLED) {
+                f.subscribe(this);
+            }
         }
 
         @Override
diff --git a/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java b/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java
index 6e80b57904..06394de7ab 100644
--- a/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java
+++ b/src/test/java/io/reactivex/rxjava3/core/XFlatMapTest.java
@@ -22,7 +22,7 @@
 import org.reactivestreams.Publisher;
 
 import io.reactivex.rxjava3.exceptions.TestException;
-import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.functions.*;
 import io.reactivex.rxjava3.observers.TestObserver;
 import io.reactivex.rxjava3.plugins.RxJavaPlugins;
 import io.reactivex.rxjava3.schedulers.Schedulers;
@@ -224,7 +224,7 @@ public Completable apply(Integer v) throws Exception {
     }
 
     @Test
-    public void observableFlowable() throws Exception {
+    public void observableObservable() throws Exception {
         List<Throwable> errors = TestHelper.trackPluginErrors();
         try {
             TestObserver<Integer> to = Observable.just(1)
@@ -505,7 +505,179 @@ public Completable apply(Integer v) throws Exception {
     }
 
     @Test
-    @Ignore
+    public void singlePublisher() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestSubscriber<Integer> ts = Single.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMapPublisher(new Function<Integer, Publisher<Integer>>() {
+                @Override
+                public Publisher<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Flowable.<Integer>error(new TestException());
+                }
+            })
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(ts);
+
+            ts.cancel();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            ts.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void singleCombiner() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Single.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMap(new Function<Integer, Single<Integer>>() {
+                @Override
+                public Single<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Single.<Integer>error(new TestException());
+                }
+            }, (a, b) -> a + b)
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void singleObservable() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Single.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMapObservable(new Function<Integer, Observable<Integer>>() {
+                @Override
+                public Observable<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Observable.<Integer>error(new TestException());
+                }
+            })
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void singleNotificationSuccess() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Single.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMap(
+                new Function<Integer, Single<Integer>>() {
+                    @Override
+                    public Single<Integer> apply(Integer v) throws Exception {
+                        sleep();
+                        return Single.<Integer>error(new TestException());
+                    }
+                },
+                new Function<Throwable, Single<Integer>>() {
+                    @Override
+                    public Single<Integer> apply(Throwable v) throws Exception {
+                        sleep();
+                        return Single.<Integer>error(new TestException());
+                    }
+                }
+            )
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void singleNotificationError() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Single.<Integer>error(new TestException())
+            .subscribeOn(Schedulers.io())
+            .flatMap(
+                new Function<Integer, Single<Integer>>() {
+                    @Override
+                    public Single<Integer> apply(Integer v) throws Exception {
+                        sleep();
+                        return Single.<Integer>error(new TestException());
+                    }
+                },
+                new Function<Throwable, Single<Integer>>() {
+                    @Override
+                    public Single<Integer> apply(Throwable v) throws Exception {
+                        sleep();
+                        return Single.<Integer>error(new TestException());
+                    }
+                }
+            )
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
     public void maybeSingle() throws Exception {
         List<Throwable> errors = TestHelper.trackPluginErrors();
         try {
@@ -537,6 +709,37 @@ public Single<Integer> apply(Integer v) throws Exception {
         }
     }
 
+    @Test
+    public void maybeSingle2() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Maybe.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMapSingle(new Function<Integer, Single<Integer>>() {
+                @Override
+                public Single<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Single.<Integer>error(new TestException());
+                }
+            })
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
     @Test
     public void maybeMaybe() throws Exception {
         List<Throwable> errors = TestHelper.trackPluginErrors();
@@ -568,6 +771,240 @@ public Maybe<Integer> apply(Integer v) throws Exception {
         }
     }
 
+    @Test
+    public void maybePublisher() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestSubscriber<Integer> ts = Maybe.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMapPublisher(new Function<Integer, Publisher<Integer>>() {
+                @Override
+                public Publisher<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Flowable.<Integer>error(new TestException());
+                }
+            })
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(ts);
+
+            ts.cancel();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            ts.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void maybeObservable() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Maybe.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMapObservable(new Function<Integer, Observable<Integer>>() {
+                @Override
+                public Observable<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Observable.<Integer>error(new TestException());
+                }
+            })
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void maybeNotificationSuccess() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Maybe.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMap(
+                new Function<Integer, Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> apply(Integer v) throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                },
+                new Function<Throwable, Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> apply(Throwable v) throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                },
+                new Supplier<Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> get() throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                }
+            )
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void maybeNotificationError() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Maybe.<Integer>error(new TestException())
+            .subscribeOn(Schedulers.io())
+            .flatMap(
+                new Function<Integer, Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> apply(Integer v) throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                },
+                new Function<Throwable, Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> apply(Throwable v) throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                },
+                new Supplier<Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> get() throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                }
+            )
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void maybeNotificationEmpty() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Maybe.<Integer>empty()
+            .subscribeOn(Schedulers.io())
+            .flatMap(
+                new Function<Integer, Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> apply(Integer v) throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                },
+                new Function<Throwable, Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> apply(Throwable v) throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                },
+                new Supplier<Maybe<Integer>>() {
+                    @Override
+                    public Maybe<Integer> get() throws Exception {
+                        sleep();
+                        return Maybe.<Integer>error(new TestException());
+                    }
+                }
+            )
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
+    @Test
+    public void maybeCombiner() throws Exception {
+        List<Throwable> errors = TestHelper.trackPluginErrors();
+        try {
+            TestObserver<Integer> to = Maybe.just(1)
+            .subscribeOn(Schedulers.io())
+            .flatMap(new Function<Integer, Maybe<Integer>>() {
+                @Override
+                public Maybe<Integer> apply(Integer v) throws Exception {
+                    sleep();
+                    return Maybe.<Integer>error(new TestException());
+                }
+            }, (a, b) -> a + b)
+            .test();
+
+            cb.await();
+
+            beforeCancelSleep(to);
+
+            to.dispose();
+
+            Thread.sleep(SLEEP_AFTER_CANCEL);
+
+            to.assertEmpty();
+
+            assertTrue(errors.toString(), errors.isEmpty());
+        } finally {
+            RxJavaPlugins.reset();
+        }
+    }
+
     @Test
     public void maybeCompletable() throws Exception {
         List<Throwable> errors = TestHelper.trackPluginErrors();
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelectorTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelectorTest.java
new file mode 100644
index 0000000000..84a2a650c4
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapBiSelectorTest.java
@@ -0,0 +1,205 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+import io.reactivex.rxjava3.functions.*;
+import io.reactivex.rxjava3.observers.TestObserver;
+import io.reactivex.rxjava3.subjects.SingleSubject;
+import io.reactivex.rxjava3.testsupport.TestHelper;
+
+public class SingleFlatMapBiSelectorTest extends RxJavaTest {
+
+    BiFunction<Integer, Integer, String> stringCombine() {
+        return new BiFunction<Integer, Integer, String>() {
+            @Override
+            public String apply(Integer a, Integer b) throws Exception {
+                return a + ":" + b;
+            }
+        };
+    }
+
+    @Test
+    public void normal() {
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                return Single.just(2);
+            }
+        }, stringCombine())
+        .test()
+        .assertResult("1:2");
+    }
+
+    @Test
+    public void errorWithJust() {
+        final int[] call = { 0 };
+
+        Single.<Integer>error(new TestException())
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                call[0]++;
+                return Single.just(1);
+            }
+        }, stringCombine())
+        .test()
+        .assertFailure(TestException.class);
+
+        assertEquals(0, call[0]);
+    }
+
+    @Test
+    public void justWithError() {
+        final int[] call = { 0 };
+
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                call[0]++;
+                return Single.<Integer>error(new TestException());
+            }
+        }, stringCombine())
+        .test()
+        .assertFailure(TestException.class);
+
+        assertEquals(1, call[0]);
+    }
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(SingleSubject.create()
+                .flatMap(new Function<Object, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Object v) throws Exception {
+                return Single.just(1);
+            }
+        }, new BiFunction<Object, Integer, Object>() {
+            @Override
+            public Object apply(Object a, Integer b) throws Exception {
+                return b;
+            }
+        }));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingle(new Function<Single<Object>, SingleSource<Object>>() {
+            @Override
+            public SingleSource<Object> apply(Single<Object> v) throws Exception {
+                return v.flatMap(new Function<Object, SingleSource<Integer>>() {
+                    @Override
+                    public SingleSource<Integer> apply(Object v) throws Exception {
+                        return Single.just(1);
+                    }
+                }, new BiFunction<Object, Integer, Object>() {
+                    @Override
+                    public Object apply(Object a, Integer b) throws Exception {
+                        return b;
+                    }
+                });
+            }
+        });
+    }
+
+    @Test
+    public void mapperThrows() {
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                throw new TestException();
+            }
+        }, stringCombine())
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void mapperReturnsNull() {
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                return null;
+            }
+        }, stringCombine())
+        .test()
+        .assertFailure(NullPointerException.class);
+    }
+
+    @Test
+    public void resultSelectorThrows() {
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                return Single.just(2);
+            }
+        }, new BiFunction<Integer, Integer, Object>() {
+            @Override
+            public Object apply(Integer a, Integer b) throws Exception {
+                throw new TestException();
+            }
+        })
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void resultSelectorReturnsNull() {
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                return Single.just(2);
+            }
+        }, new BiFunction<Integer, Integer, Object>() {
+            @Override
+            public Object apply(Integer a, Integer b) throws Exception {
+                return null;
+            }
+        })
+        .test()
+        .assertFailure(NullPointerException.class);
+    }
+
+    @Test
+    public void mapperCancels() {
+        final TestObserver<Integer> to = new TestObserver<>();
+
+        Single.just(1)
+        .flatMap(new Function<Integer, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Integer v) throws Exception {
+                to.dispose();
+                return Single.just(2);
+            }
+        }, new BiFunction<Integer, Integer, Integer>() {
+            @Override
+            public Integer apply(Integer a, Integer b) throws Exception {
+                throw new IllegalStateException();
+            }
+        })
+        .subscribeWith(to)
+        .assertEmpty();
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotificationTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotificationTest.java
new file mode 100644
index 0000000000..266acc93f2
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleFlatMapNotificationTest.java
@@ -0,0 +1,113 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.*;
+import io.reactivex.rxjava3.functions.Function;
+import io.reactivex.rxjava3.internal.functions.Functions;
+import io.reactivex.rxjava3.testsupport.*;
+
+public class SingleFlatMapNotificationTest extends RxJavaTest {
+
+    @Test
+    public void dispose() {
+        TestHelper.checkDisposed(Single.just(1)
+                .flatMap(Functions.justFunction(Single.just(1)),
+                        Functions.justFunction(Single.just(1))));
+    }
+
+    @Test
+    public void doubleOnSubscribe() {
+        TestHelper.checkDoubleOnSubscribeSingle(new Function<Single<Integer>, SingleSource<Integer>>() {
+            @Override
+            public SingleSource<Integer> apply(Single<Integer> m) throws Exception {
+                return m
+                        .flatMap(Functions.justFunction(Single.just(1)),
+                                Functions.justFunction(Single.just(1)));
+            }
+        });
+    }
+
+    @Test
+    public void onSuccessNull() {
+        Single.just(1)
+        .flatMap(Functions.justFunction((Single<Integer>)null),
+                Functions.justFunction(Single.just(1)))
+        .test()
+        .assertFailure(NullPointerException.class);
+    }
+
+    @Test
+    public void onErrorNull() {
+        TestObserverEx<Integer> to = Single.<Integer>error(new TestException())
+        .flatMap(Functions.justFunction(Single.just(1)),
+                Functions.justFunction((Single<Integer>)null))
+        .to(TestHelper.<Integer>testConsumer())
+        .assertFailure(CompositeException.class);
+
+        List<Throwable> ce = TestHelper.compositeList(to.errors().get(0));
+
+        TestHelper.assertError(ce, 0, TestException.class);
+        TestHelper.assertError(ce, 1, NullPointerException.class);
+    }
+
+    @Test
+    public void onSuccessError() {
+        Single.just(1)
+        .flatMap(Functions.justFunction(Single.<Integer>error(new TestException())),
+                Functions.justFunction((Single<Integer>)null))
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void onSucccessSuccess() {
+        Single.just(1)
+        .flatMap(v -> Single.just(2), e -> Single.just(3))
+        .test()
+        .assertResult(2);
+    }
+
+    @Test
+    public void onErrorSuccess() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new TestException())
+            .flatMap(v -> Single.just(2), e -> Single.just(3))
+            .test()
+            .assertResult(3);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+
+    @Test
+    public void onErrorError() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            Single.error(new TestException())
+            .flatMap(v -> Single.just(2), e -> Single.<Integer>error(new IOException()))
+            .test()
+            .assertFailure(IOException.class);
+
+            assertTrue("" + errors, errors.isEmpty());
+        });
+    }
+}

From 7e4bb8b0a076c3b5a4c0c3b2fb559f0ba836c88f Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Wed, 29 Jan 2020 18:42:51 +0100
Subject: [PATCH 36/37] 3.x: Add remaining Maybe marbles (+50) (#6897)

---
 .../java/io/reactivex/rxjava3/core/Maybe.java | 103 ++++++++++++------
 1 file changed, 69 insertions(+), 34 deletions(-)

diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 20e52f2f5f..66d5ad143d 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -2602,7 +2602,7 @@ public static <T, R> Maybe<R> zipArray(@NonNull Function<? super Object[], ? ext
     /**
      * Mirrors the {@link MaybeSource} (current or provided) that first signals an event.
      * <p>
-     * <img width="640" height="385" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/amb.png" alt="">
+     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.ambWith.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code ambWith} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2626,6 +2626,8 @@ public final Maybe<T> ambWith(@NonNull MaybeSource<? extends T> other) {
     /**
      * Waits in a blocking fashion until the current {@code Maybe} signals a success value (which is returned),
      * {@code null} if completed or an exception (which is propagated).
+     * <p>
+     * <img width="640" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingGet.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code blockingGet} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2648,6 +2650,8 @@ public final T blockingGet() {
     /**
      * Waits in a blocking fashion until the current {@code Maybe} signals a success value (which is returned),
      * defaultValue if completed or an exception (which is propagated).
+     * <p>
+     * <img width="640" height="297" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.blockingGet.v.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code blockingGet} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -2803,7 +2807,7 @@ public final void blockingSubscribe(@NonNull MaybeObserver<? super T> observer)
      * Returns a {@code Maybe} that subscribes to this {@code Maybe} lazily, caches its event
      * and replays it, to all the downstream subscribers.
      * <p>
-     * <img width="640" height="410" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/cache.png" alt="">
+     * <img width="640" height="244" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.cache.png" alt="">
      * <p>
      * The operator subscribes only when the first downstream subscriber subscribes and maintains
      * a single subscription towards this {@code Maybe}.
@@ -2849,6 +2853,8 @@ public final <U> Maybe<U> cast(@NonNull Class<? extends U> clazz) {
     /**
      * Transform a {@code Maybe} by applying a particular {@link MaybeTransformer} function to it.
      * <p>
+     * <img width="640" height="615" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.compose.png" alt="">
+     * <p>
      * This method operates on the {@code Maybe} itself whereas {@link #lift} operates on the {@code Maybe}'s {@link MaybeObserver}s.
      * <p>
      * If the operator you are creating is designed to act on the individual item emitted by a {@code Maybe}, use
@@ -2958,7 +2964,7 @@ public final <R> Maybe<R> concatMapSingle(@NonNull Function<? super T, ? extends
      * Returns a {@link Flowable} that emits the items emitted from the current {@code Maybe}, then the {@code other} {@link MaybeSource}, one after
      * the other, without interleaving them.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concat.png" alt="">
+     * <img width="640" height="172" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatWith.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors backpressure from downstream.</dd>
@@ -3009,7 +3015,7 @@ public final Single<Boolean> contains(@NonNull Object item) {
      * Returns a {@link Single} that counts the total number of items emitted (0 or 1) by the current {@code Maybe} and emits
      * this count as a 64-bit {@link Long}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/longCount.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.count.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code count} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3029,7 +3035,7 @@ public final Single<Long> count() {
      * Returns a {@link Single} that emits the item emitted by the current {@code Maybe} or a specified default item
      * if the current {@code Maybe} is empty.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/defaultIfEmpty.png" alt="">
+     * <img width="640" height="390" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.defaultIfEmpty.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code defaultIfEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3095,7 +3101,7 @@ public final Single<T> defaultIfEmpty(@NonNull T defaultItem) {
      * specified delay.
      * An error signal will not be delayed.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.delay.t.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -3121,7 +3127,7 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit) {
      * Returns a {@code Maybe} that signals the events emitted by the current {@code Maybe} shifted forward in time by a
      * specified delay.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
+     * <img width="640" height="340" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.delay.tb.png" alt="">
      * <dl>
      *   <dt><b>Scheduler:</b></dt>
      *   <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -3148,7 +3154,7 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit, boolean delayErro
      * specified delay.
      * An error signal will not be delayed.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
+     * <img width="640" height="434" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.delay.ts.png" alt="">
      * <dl>
      *   <dt><b>Scheduler:</b></dt>
      *   <dd>you specify the {@link Scheduler} where the non-blocking wait and emission happens</dd>
@@ -3173,7 +3179,7 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Schedule
      * Returns a {@code Maybe} that signals the events emitted by the current {@code Maybe} shifted forward in time by a
      * specified delay running on the specified {@link Scheduler}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.s.png" alt="">
+     * <img width="640" height="352" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.delay.tsb.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>you specify which {@code Scheduler} this operator will use.</dd>
@@ -3203,7 +3209,7 @@ public final Maybe<T> delay(long time, @NonNull TimeUnit unit, @NonNull Schedule
     /**
      * Delays the emission of this {@code Maybe} until the given {@link Publisher} signals an item or completes.
      * <p>
-     * <img width="640" height="450" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.oo.png" alt="">
+     * <img width="640" height="175" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.delay.p.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The {@code delayIndicator} is consumed in an unbounded manner but is cancelled after
@@ -3313,6 +3319,8 @@ public final Maybe<T> delaySubscription(long time, @NonNull TimeUnit unit, @NonN
      * Calls the specified {@link Consumer} with the success item after this item has been emitted to the downstream.
      * <p>Note that the {@code onAfterSuccess} action is shared between subscriptions and as such
      * should be thread-safe.
+     * <p>
+     * <img width="640" height="527" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doAfterSuccess.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code doAfterSuccess} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3336,7 +3344,7 @@ public final Maybe<T> doAfterSuccess(@NonNull Consumer<? super T> onAfterSuccess
      * {@link MaybeObserver#onComplete onSuccess},
      * {@link MaybeObserver#onComplete onComplete} or {@link MaybeObserver#onError onError}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/finallyDo.png" alt="">
+     * <img width="640" height="249" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doAfterTerminate.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code doAfterTerminate} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3365,7 +3373,10 @@ public final Maybe<T> doAfterTerminate(@NonNull Action onAfterTerminate) {
     /**
      * Calls the specified action after this {@code Maybe} signals {@code onSuccess}, {@code onError} or {@code onComplete} or gets disposed by
      * the downstream.
-     * <p>In case of a race between a terminal event and a dispose call, the provided {@code onFinally} action
+     * <p>
+     * <img width="640" height="247" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doFinally.png" alt="">
+     * <p>
+     * In case of a race between a terminal event and a dispose call, the provided {@code onFinally} action
      * is executed once per subscription.
      * <p>Note that the {@code onFinally} action is shared between subscriptions and as such
      * should be thread-safe.
@@ -3390,6 +3401,8 @@ public final Maybe<T> doFinally(@NonNull Action onFinally) {
     /**
      * Calls the shared {@link Action} if a {@link MaybeObserver} subscribed to the current {@code Maybe}
      * disposes the common {@link Disposable} it received via {@code onSubscribe}.
+     * <p>
+     * <img width="640" height="277" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doOnDispose.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code doOnDispose} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3524,6 +3537,8 @@ public final Maybe<T> doOnLifecycle(@NonNull Consumer<? super Disposable> onSubs
     /**
      * Calls the shared {@link Consumer} with the {@link Disposable} sent through the {@code onSubscribe} for each
      * {@link MaybeObserver} that subscribes to the current {@code Maybe}.
+     * <p>
+     * <img width="640" height="506" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doOnSubscribe.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code doOnSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3550,7 +3565,7 @@ public final Maybe<T> doOnSubscribe(@NonNull Consumer<? super Disposable> onSubs
      * Returns a {@code Maybe} instance that calls the given onTerminate callback
      * just before this {@code Maybe} completes normally or with an exception.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnTerminate.png" alt="">
+     * <img width="640" height="249" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.doOnTerminate.png" alt="">
      * <p>
      * This differs from {@code doAfterTerminate} in that this happens <em>before</em> the {@code onComplete} or
      * {@code onError} notification.
@@ -3782,7 +3797,7 @@ public final <U> Observable<U> flattenAsObservable(@NonNull Function<? super T,
      * Returns an {@link Observable} that is based on applying a specified function to the item emitted by the current {@code Maybe},
      * where that function returns an {@link ObservableSource}.
      * <p>
-     * <img width="640" height="357" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMap.png" alt="">
+     * <img width="640" height="302" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapObservable.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code flatMapObservable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -3807,7 +3822,7 @@ public final <R> Observable<R> flatMapObservable(@NonNull Function<? super T, ?
      * Returns a {@link Flowable} that emits items based on applying a specified function to the item emitted by the
      * current {@code Maybe}, where that function returns a {@link Publisher}.
      * <p>
-     * <img width="640" height="261" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapPublisher.png" alt="">
+     * <img width="640" height="312" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.flatMapPublisher.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the downstream backpressure.</dd>
@@ -3927,7 +3942,7 @@ public final Completable ignoreElement() {
     /**
      * Returns a {@link Single} that emits {@code true} if the current {@code Maybe} is empty, otherwise {@code false}.
      * <p>
-     * <img width="640" height="320" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/isEmpty.png" alt="">
+     * <img width="640" height="444" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.isEmpty.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code isEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4150,7 +4165,7 @@ public final Single<Notification<T>> materialize() {
     /**
      * Flattens this {@code Maybe} and another {@link MaybeSource} into a single {@link Flowable}, without any transformation.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/merge.png" alt="">
+     * <img width="640" height="218" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.mergeWith.png" alt="">
      * <p>
      * You can combine items emitted by multiple {@code Maybe}s so that they appear as a single {@code Flowable}, by
      * using the {@code mergeWith} method.
@@ -4231,6 +4246,8 @@ public final <U> Maybe<U> ofType(@NonNull Class<U> clazz) {
     /**
      * Calls the specified converter function during assembly time and returns its resulting value.
      * <p>
+     * <img width="640" height="731" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.to.png" alt="">
+     * <p>
      * This allows fluent conversion to any other type.
      * <dl>
      * <dt><b>Scheduler:</b></dt>
@@ -4252,6 +4269,8 @@ public final <R> R to(@NonNull MaybeConverter<T, ? extends R> converter) {
     /**
      * Converts this {@code Maybe} into a backpressure-aware {@link Flowable} instance composing cancellation
      * through.
+     * <p>
+     * <img width="640" height="346" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.toFlowable.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The returned {@code Flowable} honors the backpressure of the downstream.</dd>
@@ -4298,6 +4317,8 @@ public final Future<T> toFuture() {
     /**
      * Converts this {@code Maybe} into an {@link Observable} instance composing disposal
      * through.
+     * <p>
+     * <img width="640" height="346" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.toObservable.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code toObservable} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4318,11 +4339,14 @@ public final Observable<T> toObservable() {
     /**
      * Converts this {@code Maybe} into a {@link Single} instance composing disposal
      * through and turning an empty {@code Maybe} into a signal of {@link NoSuchElementException}.
+     * <p>
+     * <img width="640" height="361" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.toSingle.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code toSingle} does not operate by default on a particular {@link Scheduler}.</dd>
      * </dl>
      * @return the new {@code Single} instance
+     * @see #defaultIfEmpty(Object)
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
@@ -4504,7 +4528,7 @@ public final Maybe<T> onTerminateDetach() {
     /**
      * Returns a {@link Flowable} that repeats the sequence of items emitted by the current {@code Maybe} indefinitely.
      * <p>
-     * <img width="640" height="309" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeat.o.png" alt="">
+     * <img width="640" height="276" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.repeat.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors downstream backpressure.</dd>
@@ -4527,7 +4551,7 @@ public final Flowable<T> repeat() {
      * Returns a {@link Flowable} that repeats the sequence of items emitted by the current {@code Maybe} at most
      * {@code count} times.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeat.on.png" alt="">
+     * <img width="640" height="294" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.repeat.n.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This operator honors downstream backpressure.</dd>
@@ -4555,7 +4579,7 @@ public final Flowable<T> repeat(long times) {
      * Returns a {@link Flowable} that repeats the sequence of items emitted by the current {@code Maybe} until
      * the provided stop function returns {@code true}.
      * <p>
-     * <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeat.on.png" alt="">
+     * <img width="640" height="329" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.repeatUntil.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>This operator honors downstream backpressure.</dd>
@@ -4587,7 +4611,7 @@ public final Flowable<T> repeatUntil(@NonNull BooleanSupplier stop) {
      * call {@code onComplete} or {@code onError} on the child observer. Otherwise, this operator will
      * resubscribe to the current {@code Maybe}.
      * <p>
-     * <img width="640" height="430" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeatWhen.f.png" alt="">
+     * <img width="640" height="562" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.repeatWhen.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The operator honors downstream backpressure and expects the source {@code Publisher} to honor backpressure as well.
@@ -4614,7 +4638,7 @@ public final Flowable<T> repeatWhen(@NonNull Function<? super Flowable<Object>,
      * Returns a {@code Maybe} that mirrors the current {@code Maybe}, resubscribing to it if it calls {@code onError}
      * (infinite retry count).
      * <p>
-     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.png" alt="">
+     * <img width="640" height="393" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retry.png" alt="">
      * <p>
      * If the current {@code Maybe} calls {@link MaybeObserver#onError}, this operator will resubscribe to the current
      * {@code Maybe} rather than propagating the {@code onError} call.
@@ -4637,7 +4661,7 @@ public final Maybe<T> retry() {
      * Returns a {@code Maybe} that mirrors the current {@code Maybe}, resubscribing to it if it calls {@code onError}
      * and the predicate returns {@code true} for that specific exception and retry count.
      * <p>
-     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.png" alt="">
+     * <img width="640" height="230" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retry.f.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4662,7 +4686,7 @@ public final Maybe<T> retry(@NonNull BiPredicate<? super Integer, ? super Throwa
      * Returns a {@code Maybe} that mirrors the current {@code Maybe}, resubscribing to it if it calls {@code onError}
      * up to a specified number of retries.
      * <p>
-     * <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.png" alt="">
+     * <img width="640" height="329" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retry.n.png" alt="">
      * <p>
      * If the current {@code Maybe} calls {@link MaybeObserver#onError}, this operator will resubscribe to the current
      * {@code Maybe} for a maximum of {@code count} resubscriptions rather than propagating the
@@ -4687,7 +4711,8 @@ public final Maybe<T> retry(long times) {
 
     /**
      * Retries at most {@code times} or until the predicate returns {@code false}, whichever happens first.
-     *
+     * <p>
+     * <img width="640" height="259" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retry.nf.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4707,6 +4732,8 @@ public final Maybe<T> retry(long times, @NonNull Predicate<? super Throwable> pr
 
     /**
      * Retries the current {@code Maybe} if it fails and the predicate returns {@code true}.
+     * <p>
+     * <img width="640" height="240" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retry.g.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -4751,7 +4778,7 @@ public final Maybe<T> retryUntil(@NonNull BooleanSupplier stop) {
      * {@code onComplete} or {@code onError} on the child subscription. Otherwise, this operator will
      * resubscribe to the current {@code Maybe}.
      * <p>
-     * <img width="640" height="430" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retryWhen.f.png" alt="">
+     * <img width="640" height="405" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retryWhen.png" alt="">
      * <p>
      * Example:
      *
@@ -5167,7 +5194,7 @@ public final Maybe<T> subscribeOn(@NonNull Scheduler scheduler) {
      * Returns a {@code Maybe} that emits the items emitted by the current {@code Maybe} or the items of an alternate
      * {@link MaybeSource} if the current {@code Maybe} is empty.
      * <p>
-     * <img width="640" height="446" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.m.png" alt="">
+     * <img width="640" height="222" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchIfEmpty.m.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchIfEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5190,7 +5217,7 @@ public final Maybe<T> switchIfEmpty(@NonNull MaybeSource<? extends T> other) {
      * Returns a {@link Single} that emits the items emitted by the current {@code Maybe} or the item of an alternate
      * {@link SingleSource} if the current {@code Maybe} is empty.
      * <p>
-     * <img width="640" height="446" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/switchifempty.m.png" alt="">
+     * <img width="640" height="312" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.switchIfEmpty.s.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code switchIfEmpty} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5214,7 +5241,7 @@ public final Single<T> switchIfEmpty(@NonNull SingleSource<? extends T> other) {
      * Returns a {@code Maybe} that emits the items emitted by the current {@code Maybe} until a second {@link MaybeSource}
      * emits an item.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/takeUntil.png" alt="">
+     * <img width="640" height="219" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.takeUntil.m.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code takeUntil} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5241,7 +5268,7 @@ public final <U> Maybe<T> takeUntil(@NonNull MaybeSource<U> other) {
      * Returns a {@code Maybe} that emits the item emitted by the current {@code Maybe} until a second {@link Publisher}
      * emits an item.
      * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/takeUntil.png" alt="">
+     * <img width="640" height="199" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.takeUntil.p.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The {@code Publisher} is consumed in an unbounded fashion and is cancelled after the first item
@@ -5499,7 +5526,7 @@ public final Maybe<Timed<T>> timestamp(@NonNull TimeUnit unit, @NonNull Schedule
      * item. If the next item isn't emitted within the specified timeout duration starting from its predecessor,
      * the resulting {@code Maybe} terminates and notifies {@link MaybeObserver}s of a {@link TimeoutException}.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/timeout.1.png" alt="">
+     * <img width="640" height="261" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.t.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code timeout} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -5525,7 +5552,7 @@ public final Maybe<T> timeout(long timeout, @NonNull TimeUnit unit) {
      * item. If the next item isn't emitted within the specified timeout duration starting from its predecessor,
      * the current {@code Maybe} is disposed and resulting {@code Maybe} begins instead to mirror a fallback {@link MaybeSource}.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/timeout.2.png" alt="">
+     * <img width="640" height="226" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.tm.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This version of {@code timeout} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -5555,7 +5582,7 @@ public final Maybe<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull May
      * starting from its predecessor, the current {@code Maybe} is disposed and resulting {@code Maybe} begins instead
      * to mirror a fallback {@link MaybeSource}.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/timeout.2s.png" alt="">
+     * <img width="640" height="227" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.tsm.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
@@ -5587,7 +5614,7 @@ public final Maybe<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Sch
      * specified timeout duration starting from its predecessor, the resulting {@code Maybe} terminates and
      * notifies {@link MaybeObserver}s of a {@link TimeoutException}.
      * <p>
-     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/timeout.1s.png" alt="">
+     * <img width="640" height="261" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.ts.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>You specify which {@code Scheduler} this operator will use.</dd>
@@ -5613,6 +5640,8 @@ public final Maybe<T> timeout(long timeout, @NonNull TimeUnit unit, @NonNull Sch
     /**
      * If the current {@code Maybe} didn't signal an event before the {@code timeoutIndicator} {@link MaybeSource} signals, a
      * {@link TimeoutException} is signaled instead.
+     * <p>
+     * <img width="640" height="235" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.m.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code timeout} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5635,6 +5664,8 @@ public final <U> Maybe<T> timeout(@NonNull MaybeSource<U> timeoutIndicator) {
      * If the current {@code Maybe} didn't signal an event before the {@code timeoutIndicator} {@link MaybeSource} signals,
      * the current {@code Maybe} is disposed and the {@code fallback} {@code MaybeSource} subscribed to
      * as a continuation.
+     * <p>
+     * <img width="640" height="194" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.mm.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code timeout} does not operate by default on a particular {@link Scheduler}.</dd>
@@ -5658,6 +5689,8 @@ public final <U> Maybe<T> timeout(@NonNull MaybeSource<U> timeoutIndicator, @Non
     /**
      * If the current {@code Maybe} source didn't signal an event before the {@code timeoutIndicator} {@link Publisher} signals, a
      * {@link TimeoutException} is signaled instead.
+     * <p>
+     * <img width="640" height="212" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.p.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The {@code timeoutIndicator} {@code Publisher} is consumed in an unbounded manner and
@@ -5684,6 +5717,8 @@ public final <U> Maybe<T> timeout(@NonNull Publisher<U> timeoutIndicator) {
      * If the current {@code Maybe} didn't signal an event before the {@code timeoutIndicator} {@link Publisher} signals,
      * the current {@code Maybe} is disposed and the {@code fallback} {@link MaybeSource} subscribed to
      * as a continuation.
+     * <p>
+     * <img width="640" height="169" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.timeout.pm.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>The {@code timeoutIndicator} {@code Publisher} is consumed in an unbounded manner and

From 81f0569a8b9b7d27059f127b90fd7335118b2ee4 Mon Sep 17 00:00:00 2001
From: David Karnok <akarnokd@gmail.com>
Date: Thu, 30 Jan 2020 16:14:12 +0100
Subject: [PATCH 37/37] 3.x: Add concatEagerDelayError across (#6899)

* 3.x: Add concatEagerDelayError across

* Add more since 3.0.0 tags
---
 docs/Operator-Matrix.md                       | 258 +++++++++---------
 .../reactivex/rxjava3/core/Completable.java   |   1 +
 .../io/reactivex/rxjava3/core/Flowable.java   | 171 +++++++++++-
 .../java/io/reactivex/rxjava3/core/Maybe.java | 206 +++++++++++++-
 .../io/reactivex/rxjava3/core/Observable.java | 156 +++++++++--
 .../io/reactivex/rxjava3/core/Single.java     | 252 +++++++++++++++--
 .../flowable/FlowableConcatMapEagerTest.java  |  46 +++-
 .../operators/maybe/MaybeConcatEagerTest.java | 152 +++++++++++
 .../ObservableConcatMapEagerTest.java         |  44 +++
 .../single/SingleConcatEagerTest.java         | 141 ++++++++++
 .../internal/util/MarbleDimensions.java       |   2 +-
 .../validators/ParamValidationNaming.java     |   1 +
 12 files changed, 1238 insertions(+), 192 deletions(-)
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatEagerTest.java
 create mode 100644 src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatEagerTest.java

diff --git a/docs/Operator-Matrix.md b/docs/Operator-Matrix.md
index dfa16162e7..afeb8e4182 100644
--- a/docs/Operator-Matrix.md
+++ b/docs/Operator-Matrix.md
@@ -37,69 +37,69 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='concatArrayEagerDelayError'></a>`concatArrayEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeArrayDelayError().'>([25](#notes-25))</sup>|
 <a name='concatDelayError'></a>`concatDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='concatEager'></a>`concatEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use merge().'>([26](#notes-26))</sup>|
-<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapCompletableDelayError'></a>`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([28](#notes-28))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapDelayError'></a>`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatMap.'>([32](#notes-32))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([33](#notes-33))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatMap().'>([34](#notes-34))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='concatEagerDelayError'></a>`concatEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='No items to keep ordered. Use mergeDelayError().'>([27](#notes-27))</sup>|
+<a name='concatMap'></a>`concatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapCompletable'></a>`concatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapCompletableDelayError'></a>`concatMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use concatMapCompletable.'>([29](#notes-29))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapDelayError'></a>`concatMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMap.'>([30](#notes-30))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapEager'></a>`concatMapEager`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapEagerDelayError'></a>`concatMapEagerDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item to map. Use concatMap().'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapIterable'></a>`concatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapMaybe'></a>`concatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatMap.'>([33](#notes-33))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapMaybeDelayError'></a>`concatMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([34](#notes-34))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapMaybe.'>([34](#notes-34))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapSingle'></a>`concatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use concatMap().'>([35](#notes-35))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapSingleDelayError'></a>`concatMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use concatMapSingle.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='concatMapStream'></a>`concatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
 <a name='concatWith'></a>`concatWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='contains'></a>`contains`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([38](#notes-38))</sup>|
+<a name='count'></a>`count`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty thus always 1.'>([38](#notes-38))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus always 0.'>([39](#notes-39))</sup>|
 <a name='create'></a>`create`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
+<a name='debounce'></a>`debounce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='defaultIfEmpty'></a>`defaultIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([42](#notes-42))</sup>|
 <a name='defer'></a>`defer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delay'></a>`delay`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='delaySubscription'></a>`delaySubscription`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([42](#notes-42))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([44](#notes-44))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='dematerialize'></a>`dematerialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='distinct'></a>`distinct`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='distinctUntilChanged'></a>`distinctUntilChanged`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, always distinct.'>([43](#notes-43))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='doAfterNext'></a>`doAfterNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterSuccess().'>([44](#notes-44))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='doAfterSuccess'></a>`doAfterSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doAfterNext().'>([45](#notes-45))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
 <a name='doAfterTerminate'></a>`doAfterTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doFinally'></a>`doFinally`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([45](#notes-45))</sup>|
-<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([46](#notes-46))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([47](#notes-47))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([48](#notes-48))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='doOnCancel'></a>`doOnCancel`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([46](#notes-46))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnDispose().'>([46](#notes-46))</sup>|
+<a name='doOnComplete'></a>`doOnComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always succeeds or fails, there is no onComplete signal.'>([47](#notes-47))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnDispose'></a>`doOnDispose`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnCancel().'>([48](#notes-48))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEach'></a>`doOnEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([49](#notes-49))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use doOnEvent().'>([49](#notes-49))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
 <a name='doOnError'></a>`doOnError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([49](#notes-49))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([49](#notes-49))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
+<a name='doOnEvent'></a>`doOnEvent`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use doOnEach().'>([50](#notes-50))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='doOnLifecycle'></a>`doOnLifecycle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([50](#notes-50))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
+<a name='doOnNext'></a>`doOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnSuccess().'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='doOnRequest'></a>`doOnRequest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|
 <a name='doOnSubscribe'></a>`doOnSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([52](#notes-52))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='doOnSuccess'></a>`doOnSuccess`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Different terminology. Use doOnNext().'>([53](#notes-53))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
 <a name='doOnTerminate'></a>`doOnTerminate`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([53](#notes-53))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([56](#notes-56))</sup>|
+<a name='elementAt'></a>`elementAt`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use defaultIfEmpty.'>([54](#notes-54))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='elementAtOrError'></a>`elementAtOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item with index 0. Use toSingle.'>([56](#notes-56))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item with index 0.'>([55](#notes-55))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='empty'></a>`empty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use complete().'>([57](#notes-57))</sup>|
 <a name='error'></a>`error`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
-<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([61](#notes-61))</sup>|
-<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([63](#notes-63))</sup>|
-<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|
-<a name='flatMap'></a>`flatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapCompletable'></a>`flatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([31](#notes-31))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([64](#notes-64))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([66](#notes-66))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([64](#notes-64))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapSingleElement'></a>`flatMapSingleElement`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([68](#notes-68))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapSingle.'>([68](#notes-68))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([36](#notes-36))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='filter'></a>`filter`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='first'></a>`first`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([42](#notes-42))</sup>|
+<a name='firstElement'></a>`firstElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='firstOrError'></a>`firstOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([62](#notes-62))</sup>|
+<a name='firstOrErrorStage'></a>`firstOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([64](#notes-64))</sup>|
+<a name='firstStage'></a>`firstStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|
+<a name='flatMap'></a>`flatMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapCompletable'></a>`flatMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapIterable'></a>`flatMapIterable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenAsFlowable.'>([32](#notes-32))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapMaybe'></a>`flatMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([65](#notes-65))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapObservable'></a>`flatMapObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([66](#notes-66))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([67](#notes-67))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapPublisher'></a>`flatMapPublisher`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap.'>([67](#notes-67))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Not supported. Use flatMap.'>([68](#notes-68))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapSingle'></a>`flatMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMap().'>([65](#notes-65))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flatMapStream'></a>`flatMapStream`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flattenStreamAsFlowable.'>([37](#notes-37))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flattenAsFlowable'></a>`flattenAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flattenAsObservable'></a>`flattenAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapIterable().'>([69](#notes-69))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flattenStreamAsFlowable'></a>`flattenStreamAsFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='flattenStreamAsObservable'></a>`flattenStreamAsObservable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use flatMapStream().'>([70](#notes-70))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
 <a name='forEach'></a>`forEach`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|
 <a name='forEachWhile'></a>`forEachWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use subscribe().'>([71](#notes-71))</sup>|
 <a name='fromAction'></a>`fromAction`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -125,17 +125,17 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='ignoreElements'></a>`ignoreElements`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use ignoreElement().'>([82](#notes-82))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='interval'></a>`interval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|
 <a name='intervalRange'></a>`intervalRange`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use timer().'>([83](#notes-83))</sup>|
-<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='isEmpty'></a>`isEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='join'></a>`join`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use zip()'>([84](#notes-84))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to join.'>([80](#notes-80))</sup>|
 <a name='just'></a>`just`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
-<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([61](#notes-61))</sup>|
-<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([63](#notes-63))</sup>|
-<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|
+<a name='last'></a>`last`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([42](#notes-42))</sup>|
+<a name='lastElement'></a>`lastElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='lastOrError'></a>`lastOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([62](#notes-62))</sup>|
+<a name='lastOrErrorStage'></a>`lastOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([64](#notes-64))</sup>|
+<a name='lastStage'></a>`lastStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|
 <a name='lift'></a>`lift`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='map'></a>`map`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='mapOptional'></a>`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='map'></a>`map`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='mapOptional'></a>`mapOptional`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
 <a name='materialize'></a>`materialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='merge'></a>`merge`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='mergeArray'></a>`mergeArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -145,9 +145,9 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='never'></a>`never`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='observeOn'></a>`observeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='ofType'></a>`ofType`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to filter.'>([85](#notes-85))</sup>|
-<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
-<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
-<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
+<a name='onBackpressureBuffer'></a>`onBackpressureBuffer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|
+<a name='onBackpressureDrop'></a>`onBackpressureDrop`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|
+<a name='onBackpressureLatest'></a>`onBackpressureLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|
 <a name='onErrorComplete'></a>`onErrorComplete`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeNext'></a>`onErrorResumeNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='onErrorResumeWith'></a>`onErrorResumeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -158,7 +158,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='publish'></a>`publish`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
 <a name='range'></a>`range`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
 <a name='rangeLong'></a>`rangeLong`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use just().'>([90](#notes-90))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use complete().'>([74](#notes-74))</sup>|
-<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([51](#notes-51))</sup>|
+<a name='rebatchRequests'></a>`rebatchRequests`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Backpressure related and not supported outside Flowable.'>([52](#notes-52))</sup>|
 <a name='reduce'></a>`reduce`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='reduceWith'></a>`reduceWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='repeat'></a>`repeat`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -169,19 +169,19 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='retryUntil'></a>`retryUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='retryWhen'></a>`retryWhen`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='safeSubscribe'></a>`safeSubscribe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='sample'></a>`sample`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
 <a name='scan'></a>`scan`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='scanWith'></a>`scanWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use map().'>([91](#notes-91))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to reduce.'>([92](#notes-92))</sup>|
 <a name='sequenceEqual'></a>`sequenceEqual`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='serialize'></a>`serialize`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one signal type.'>([93](#notes-93))</sup>|
 <a name='share'></a>`share`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a MaybeSubject.'>([87](#notes-87))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a SingleSubject.'>([88](#notes-88))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Connectable sources not supported outside Flowable and Observable. Use a ConnectableSubject.'>([89](#notes-89))</sup>|
-<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([57](#notes-57))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([41](#notes-41))</sup>|
-<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
-<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([61](#notes-61))</sup>|
-<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([63](#notes-63))</sup>|
-<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([62](#notes-62))</sup>|
-<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
-<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
+<a name='single'></a>`single`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use defaultIfEmpty.'>([58](#notes-58))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen() to chose the follow-up sequence.'>([42](#notes-42))</sup>|
+<a name='singleElement'></a>`singleElement`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
+<a name='singleOrError'></a>`singleOrError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always one item, would be no-op.'>([61](#notes-61))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([62](#notes-62))</sup>|
+<a name='singleOrErrorStage'></a>`singleOrErrorStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use andThen().'>([64](#notes-64))</sup>|
+<a name='singleStage'></a>`singleStage`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use toCompletionStage().'>([63](#notes-63))</sup>|
+<a name='skip'></a>`skip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|
+<a name='skipLast'></a>`skipLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|
 <a name='skipUntil'></a>`skipUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use takeUntil().'>([94](#notes-94))</sup>|
 <a name='skipWhile'></a>`skipWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='sorted'></a>`sorted`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item.'>([78](#notes-78))</sup>|
@@ -193,29 +193,29 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='subscribeOn'></a>`subscribeOn`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='subscribeWith'></a>`subscribeWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='switchIfEmpty'></a>`switchIfEmpty`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Never empty.'>([23](#notes-23))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty. Use defaultIfEmpty().'>([99](#notes-99))</sup>|
-<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
-<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([27](#notes-27))</sup>|
+<a name='switchMap'></a>`switchMap`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapCompletable'></a>`switchMapCompletable`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapCompletableDelayError'></a>`switchMapCompletableDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapDelayError'></a>`switchMapDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapMaybe'></a>`switchMapMaybe`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapMaybeDelayError'></a>`switchMapMaybeDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapSingle'></a>`switchMapSingle`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
+<a name='switchMapSingleDelayError'></a>`switchMapSingleDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use flatMap().'>([100](#notes-100))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to map.'>([28](#notes-28))</sup>|
 <a name='switchOnNext'></a>`switchOnNext`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='switchOnNextDelayError'></a>`switchOnNextDelayError`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
-<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([59](#notes-59))</sup>|
+<a name='take'></a>`take`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|
+<a name='takeLast'></a>`takeLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item, would be no-op.'>([60](#notes-60))</sup>|
 <a name='takeUntil'></a>`takeUntil`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='takeWhile'></a>`takeWhile`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item. Use filter().'>([95](#notes-95))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty.'>([2](#notes-2))</sup>|
 <a name='test'></a>`test`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([39](#notes-39))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
-<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='throttleFirst'></a>`throttleFirst`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='throttleLast'></a>`throttleLast`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='throttleLatest'></a>`throttleLatest`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='throttleWithTimeout'></a>`throttleWithTimeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='At most one item signaled so no subsequent items to work with.'>([40](#notes-40))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
+<a name='timeInterval'></a>`timeInterval`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
 <a name='timeout'></a>`timeout`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='timer'></a>`timer`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
-<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([40](#notes-40))</sup>|
+<a name='timestamp'></a>`timestamp`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Always empty thus no items to work with.'>([41](#notes-41))</sup>|
 <a name='to'></a>`to`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toCompletionStage'></a>`toCompletionStage`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([101](#notes-101))</sup>|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use firstStage.'>([101](#notes-101))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
 <a name='toFlowable'></a>`toFlowable`|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Would be no-op.'>([102](#notes-102))</sup>|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|
@@ -237,7 +237,7 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='zip'></a>`zip`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use merge().'>([111](#notes-111))</sup>|
 <a name='zipArray'></a>`zipArray`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeArray().'>([112](#notes-112))</sup>|
 <a name='zipWith'></a>`zipWith`|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![present](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_on.png)|![absent](https://raw.github.com/wiki/ReactiveX/RxJava/images/checkmark_off.png) <sup title='Use mergeWith().'>([113](#notes-113))</sup>|
-<a name='total'></a>**237 operators** | **215** | **209** | **118** | **107** | **84** |
+<a name='total'></a>**237 operators** | **216** | **210** | **118** | **108** | **84** |
 
 #### Notes
 <a name='notes-1'></a><sup>1</sup> Use [`contains()`](#contains).<br/>
@@ -266,48 +266,48 @@ Operator | ![Flowable](https://raw.github.com/wiki/ReactiveX/RxJava/images/opmat
 <a name='notes-24'></a><sup>24</sup> No items to keep ordered. Use [`mergeArray()`](#mergeArray).<br/>
 <a name='notes-25'></a><sup>25</sup> No items to keep ordered. Use [`mergeArrayDelayError()`](#mergeArrayDelayError).<br/>
 <a name='notes-26'></a><sup>26</sup> No items to keep ordered. Use [`merge()`](#merge).<br/>
-<a name='notes-27'></a><sup>27</sup> Always empty thus no items to map.<br/>
-<a name='notes-28'></a><sup>28</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use [`concatMapCompletable`](#concatMapCompletable).<br/>
-<a name='notes-29'></a><sup>29</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMap`](#concatMap).<br/>
-<a name='notes-30'></a><sup>30</sup> At most one item to map. Use [`concatMap()`](#concatMap).<br/>
-<a name='notes-31'></a><sup>31</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
-<a name='notes-32'></a><sup>32</sup> Use [`concatMap`](#concatMap).<br/>
-<a name='notes-33'></a><sup>33</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).<br/>
-<a name='notes-34'></a><sup>34</sup> Use [`concatMap()`](#concatMap).<br/>
-<a name='notes-35'></a><sup>35</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).<br/>
-<a name='notes-36'></a><sup>36</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
-<a name='notes-37'></a><sup>37</sup> Never empty thus always 1.<br/>
-<a name='notes-38'></a><sup>38</sup> Always empty thus always 0.<br/>
-<a name='notes-39'></a><sup>39</sup> At most one item signaled so no subsequent items to work with.<br/>
-<a name='notes-40'></a><sup>40</sup> Always empty thus no items to work with.<br/>
-<a name='notes-41'></a><sup>41</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
-<a name='notes-42'></a><sup>42</sup> At most one item, always distinct.<br/>
-<a name='notes-43'></a><sup>43</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
-<a name='notes-44'></a><sup>44</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
-<a name='notes-45'></a><sup>45</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
-<a name='notes-46'></a><sup>46</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
-<a name='notes-47'></a><sup>47</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
-<a name='notes-48'></a><sup>48</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
-<a name='notes-49'></a><sup>49</sup> Use [`doOnEach()`](#doOnEach).<br/>
-<a name='notes-50'></a><sup>50</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
-<a name='notes-51'></a><sup>51</sup> Backpressure related and not supported outside `Flowable`.<br/>
-<a name='notes-52'></a><sup>52</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
-<a name='notes-53'></a><sup>53</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
-<a name='notes-54'></a><sup>54</sup> Always one item with index 0.<br/>
-<a name='notes-55'></a><sup>55</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
-<a name='notes-56'></a><sup>56</sup> Use [`complete()`](#complete).<br/>
-<a name='notes-57'></a><sup>57</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
-<a name='notes-58'></a><sup>58</sup> Always one item.<br/>
-<a name='notes-59'></a><sup>59</sup> At most one item, would be no-op.<br/>
-<a name='notes-60'></a><sup>60</sup> Always one item, would be no-op.<br/>
-<a name='notes-61'></a><sup>61</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
-<a name='notes-62'></a><sup>62</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
-<a name='notes-63'></a><sup>63</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
-<a name='notes-64'></a><sup>64</sup> Use [`flatMap()`](#flatMap).<br/>
-<a name='notes-65'></a><sup>65</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
-<a name='notes-66'></a><sup>66</sup> Use [`flatMap`](#flatMap).<br/>
-<a name='notes-67'></a><sup>67</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
-<a name='notes-68'></a><sup>68</sup> Use [`flatMapSingle`](#flatMapSingle).<br/>
+<a name='notes-27'></a><sup>27</sup> No items to keep ordered. Use [`mergeDelayError()`](#mergeDelayError).<br/>
+<a name='notes-28'></a><sup>28</sup> Always empty thus no items to map.<br/>
+<a name='notes-29'></a><sup>29</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both. Use [`concatMapCompletable`](#concatMapCompletable).<br/>
+<a name='notes-30'></a><sup>30</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMap`](#concatMap).<br/>
+<a name='notes-31'></a><sup>31</sup> At most one item to map. Use [`concatMap()`](#concatMap).<br/>
+<a name='notes-32'></a><sup>32</sup> At most one item. Use [`flattenAsFlowable`](#flattenAsFlowable) or [`flattenAsObservable`](#flattenAsObservable).<br/>
+<a name='notes-33'></a><sup>33</sup> Use [`concatMap`](#concatMap).<br/>
+<a name='notes-34'></a><sup>34</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapMaybe`](#concatMapMaybe).<br/>
+<a name='notes-35'></a><sup>35</sup> Use [`concatMap()`](#concatMap).<br/>
+<a name='notes-36'></a><sup>36</sup> Either the upstream fails (thus no inner) or the mapped-in source, but never both.  Use [`concatMapSingle`](#concatMapSingle).<br/>
+<a name='notes-37'></a><sup>37</sup> At most one item. Use [`flattenStreamAsFlowable`](#flattenStreamAsFlowable) or [`flattenStreamAsObservable`](#flattenStreamAsObservable).<br/>
+<a name='notes-38'></a><sup>38</sup> Never empty thus always 1.<br/>
+<a name='notes-39'></a><sup>39</sup> Always empty thus always 0.<br/>
+<a name='notes-40'></a><sup>40</sup> At most one item signaled so no subsequent items to work with.<br/>
+<a name='notes-41'></a><sup>41</sup> Always empty thus no items to work with.<br/>
+<a name='notes-42'></a><sup>42</sup> Always empty. Use [`andThen()`](#andThen) to chose the follow-up sequence.<br/>
+<a name='notes-43'></a><sup>43</sup> At most one item, always distinct.<br/>
+<a name='notes-44'></a><sup>44</sup> Different terminology. Use [`doAfterSuccess()`](#doAfterSuccess).<br/>
+<a name='notes-45'></a><sup>45</sup> Different terminology. Use [`doAfterNext()`](#doAfterNext).<br/>
+<a name='notes-46'></a><sup>46</sup> Different terminology. Use [`doOnDispose()`](#doOnDispose).<br/>
+<a name='notes-47'></a><sup>47</sup> Always succeeds or fails, there is no `onComplete` signal.<br/>
+<a name='notes-48'></a><sup>48</sup> Different terminology. Use [`doOnCancel()`](#doOnCancel).<br/>
+<a name='notes-49'></a><sup>49</sup> At most one item. Use [`doOnEvent()`](#doOnEvent).<br/>
+<a name='notes-50'></a><sup>50</sup> Use [`doOnEach()`](#doOnEach).<br/>
+<a name='notes-51'></a><sup>51</sup> Different terminology. Use [`doOnSuccess()`](#doOnSuccess).<br/>
+<a name='notes-52'></a><sup>52</sup> Backpressure related and not supported outside `Flowable`.<br/>
+<a name='notes-53'></a><sup>53</sup> Different terminology. Use [`doOnNext()`](#doOnNext).<br/>
+<a name='notes-54'></a><sup>54</sup> At most one item with index 0. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-55'></a><sup>55</sup> Always one item with index 0.<br/>
+<a name='notes-56'></a><sup>56</sup> At most one item with index 0. Use [`toSingle`](#toSingle).<br/>
+<a name='notes-57'></a><sup>57</sup> Use [`complete()`](#complete).<br/>
+<a name='notes-58'></a><sup>58</sup> At most one item. Use [`defaultIfEmpty`](#defaultIfEmpty).<br/>
+<a name='notes-59'></a><sup>59</sup> Always one item.<br/>
+<a name='notes-60'></a><sup>60</sup> At most one item, would be no-op.<br/>
+<a name='notes-61'></a><sup>61</sup> Always one item, would be no-op.<br/>
+<a name='notes-62'></a><sup>62</sup> Always empty. Use [`andThen()`](#andThen) and [`error()`](#error).<br/>
+<a name='notes-63'></a><sup>63</sup> At most one item. Use [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-64'></a><sup>64</sup> Always empty. Use [`andThen()`](#andThen), [`error()`](#error) and [`toCompletionStage()`](#toCompletionStage).<br/>
+<a name='notes-65'></a><sup>65</sup> Use [`flatMap()`](#flatMap).<br/>
+<a name='notes-66'></a><sup>66</sup> Not supported. Use [`flatMap`](#flatMap) and [`toFlowable()`](#toFlowable).<br/>
+<a name='notes-67'></a><sup>67</sup> Use [`flatMap`](#flatMap).<br/>
+<a name='notes-68'></a><sup>68</sup> Not supported. Use [`flatMap`](#flatMap) and [`toObservable()`](#toFlowable).<br/>
 <a name='notes-69'></a><sup>69</sup> Use [`flatMapIterable()`](#flatMapIterable).<br/>
 <a name='notes-70'></a><sup>70</sup> Use [`flatMapStream()`](#flatMapStream).<br/>
 <a name='notes-71'></a><sup>71</sup> Use [`subscribe()`](#subscribe).<br/>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Completable.java b/src/main/java/io/reactivex/rxjava3/core/Completable.java
index cfdd87067d..682a493849 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Completable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Completable.java
@@ -1050,6 +1050,7 @@ public static Completable mergeDelayError(@NonNull Publisher<@NonNull ? extends
      *                       at a time to the inner {@code CompletableSource}s
      * @return the new {@code Completable} instance
      * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
diff --git a/src/main/java/io/reactivex/rxjava3/core/Flowable.java b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
index 58ffd3d6f8..ddf5b3cf7b 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Flowable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Flowable.java
@@ -1648,9 +1648,80 @@ public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? ext
         return fromPublisher(sources).concatMapDelayError((Function)Functions.identity(), tillTheEnd, prefetch);
     }
 
+    /**
+     * Concatenates a sequence of {@link Publisher}s eagerly into a single stream of values.
+     * <p>
+     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEager.i.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * source {@code Publisher}s. The operator buffers the values emitted by these {@code Publisher}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the inner {@code Publisher}s are
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code Publisher}s that need to be eagerly concatenated
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 2.0
+     */
+    @CheckReturnValue
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends Publisher<@NonNull ? extends T>> sources) {
+        return concatEager(sources, bufferSize(), bufferSize());
+    }
+
+    /**
+     * Concatenates a sequence of {@link Publisher}s eagerly into a single stream of values and
+     * runs a limited number of inner sequences at once.
+     * <p>
+     * <img width="640" height="375" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEager.in.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * source {@code Publisher}s. The operator buffers the values emitted by these {@code Publisher}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and both the outer and inner {@code Publisher}s are
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code Publisher}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code Publisher}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code Publisher}s can be active at the same time
+     * @param prefetch the number of elements to prefetch from each inner {@code Publisher} source
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} or {@code prefetch} is non-positive
+     * @since 2.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends Publisher<@NonNull ? extends T>> sources, int maxConcurrency, int prefetch) {
+        Objects.requireNonNull(sources, "sources is null");
+        ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
+        ObjectHelper.verifyPositive(prefetch, "prefetch");
+        return RxJavaPlugins.onAssembly(new FlowableConcatMapEager(new FlowableFromIterable(sources), Functions.identity(), maxConcurrency, prefetch, ErrorMode.BOUNDARY));
+    }
+
     /**
      * Concatenates a {@link Publisher} sequence of {@code Publisher}s eagerly into a single stream of values.
      * <p>
+     * <img width="640" height="490" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEager.p.png" alt="">
+     * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * emitted source {@code Publisher}s as they are observed. The operator buffers the values emitted by these
      * {@code Publisher}s and then drains them in order, each one after the previous one completes.
@@ -1677,7 +1748,10 @@ public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends
     }
 
     /**
-     * Concatenates a {@link Publisher} sequence of {@code Publisher}s eagerly into a single stream of values.
+     * Concatenates a {@link Publisher} sequence of {@code Publisher}s eagerly into a single stream of values and
+     * runs a limited number of inner sequences at once.
+     * <p>
+     * <img width="640" height="421" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEager.pn.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * emitted source {@code Publisher}s as they are observed. The operator buffers the values emitted by these
@@ -1713,7 +1787,10 @@ public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends
     }
 
     /**
-     * Concatenates a sequence of {@link Publisher}s eagerly into a single stream of values.
+     * Concatenates a sequence of {@link Publisher}s eagerly into a single stream of values,
+     * delaying errors until all the inner sequences terminate.
+     * <p>
+     * <img width="640" height="428" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEagerDelayError.i.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * source {@code Publisher}s. The operator buffers the values emitted by these {@code Publisher}s and then drains them
@@ -1730,18 +1807,22 @@ public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends
      * @param sources a sequence of {@code Publisher}s that need to be eagerly concatenated
      * @return the new {@code Flowable} instance with the specified concatenation behavior
      * @throws NullPointerException if {@code sources} is {@code null}
-     * @since 2.0
+     * @since 3.0.0
      */
     @CheckReturnValue
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends Publisher<@NonNull ? extends T>> sources) {
-        return concatEager(sources, bufferSize(), bufferSize());
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends Publisher<@NonNull ? extends T>> sources) {
+        return concatEagerDelayError(sources, bufferSize(), bufferSize());
     }
 
     /**
-     * Concatenates a sequence of {@link Publisher}s eagerly into a single stream of values.
+     * Concatenates a sequence of {@link Publisher}s eagerly into a single stream of values,
+     * delaying errors until all the inner sequences terminate and runs a limited number
+     * of inner sequences at once.
+     * <p>
+     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEagerDelayError.in.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * source {@code Publisher}s. The operator buffers the values emitted by these {@code Publisher}s and then drains them
@@ -1762,18 +1843,89 @@ public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends P
      * @return the new {@code Flowable} instance with the specified concatenation behavior
      * @throws NullPointerException if {@code sources} is {@code null}
      * @throws IllegalArgumentException if {@code maxConcurrency} or {@code prefetch} is non-positive
-     * @since 2.0
+     * @since 3.0.0
      */
     @CheckReturnValue
     @NonNull
     @BackpressureSupport(BackpressureKind.FULL)
     @SchedulerSupport(SchedulerSupport.NONE)
     @SuppressWarnings({ "rawtypes", "unchecked" })
-    public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends Publisher<@NonNull ? extends T>> sources, int maxConcurrency, int prefetch) {
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends Publisher<@NonNull ? extends T>> sources, int maxConcurrency, int prefetch) {
         Objects.requireNonNull(sources, "sources is null");
         ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
         ObjectHelper.verifyPositive(prefetch, "prefetch");
-        return RxJavaPlugins.onAssembly(new FlowableConcatMapEager(new FlowableFromIterable(sources), Functions.identity(), maxConcurrency, prefetch, ErrorMode.IMMEDIATE));
+        return RxJavaPlugins.onAssembly(new FlowableConcatMapEager(new FlowableFromIterable(sources), Functions.identity(), maxConcurrency, prefetch, ErrorMode.END));
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@code Publisher}s eagerly into a single stream of values,
+     * delaying errors until all the inner and the outer sequences terminate.
+     * <p>
+     * <img width="640" height="496" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEagerDelayError.p.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code Publisher}s as they are observed. The operator buffers the values emitted by these
+     * {@code Publisher}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and both the outer and inner {@code Publisher}s are
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code Publisher}s that need to be eagerly concatenated
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Publisher<@NonNull ? extends Publisher<@NonNull ? extends T>> sources) {
+        return concatEagerDelayError(sources, bufferSize(), bufferSize());
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@code Publisher}s eagerly into a single stream of values,
+     * delaying errors until all the inner and outer sequences terminate and runs a limited number of inner
+     * sequences at once.
+     * <p>
+     * <img width="640" height="421" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Flowable.concatEagerDelayError.pn.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code Publisher}s as they are observed. The operator buffers the values emitted by these
+     * {@code Publisher}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and both the outer and inner {@code Publisher}s are
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code Publisher}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code Publisher}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code Publisher}s can be active at the same time
+     * @param prefetch the number of elements to prefetch from each inner {@code Publisher} source
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} or {@code prefetch} is non-positive
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @NonNull
+    @BackpressureSupport(BackpressureKind.FULL)
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Publisher<@NonNull ? extends Publisher<@NonNull ? extends T>> sources, int maxConcurrency, int prefetch) {
+        Objects.requireNonNull(sources, "sources is null");
+        ObjectHelper.verifyPositive(maxConcurrency, "maxConcurrency");
+        ObjectHelper.verifyPositive(prefetch, "prefetch");
+        return RxJavaPlugins.onAssembly(new FlowableConcatMapEagerPublisher(sources, Functions.identity(), maxConcurrency, prefetch, ErrorMode.END));
     }
 
     /**
@@ -10134,6 +10286,7 @@ public final <R> Flowable<R> flatMap(@NonNull Function<? super T, ? extends Publ
      *            if {@code false}, the first one signaling an exception will terminate the whole sequence immediately
      * @return the new {@code Flowable} instance
      * @throws NullPointerException if {@code mapper} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
      * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
      * @since 2.0
      */
diff --git a/src/main/java/io/reactivex/rxjava3/core/Maybe.java b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
index 66d5ad143d..784343922d 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Maybe.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Maybe.java
@@ -561,11 +561,11 @@ public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? ext
     /**
      * Concatenates a sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence.
      * <p>
+     * <img width="640" height="526" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEager.i.png" alt="">
+     * <p>
      * Eager concatenation means that once an observer subscribes, this operator subscribes to all of the
      * source {@code MaybeSource}s. The operator buffers the values emitted by these {@code MaybeSource}s and then drains them
      * in order, each one after the previous one completes.
-     * <p>
-     * <img width="640" height="526" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEager.i.png" alt="">
      * <dl>
      *  <dt><b>Backpressure:</b></dt>
      *  <dd>Backpressure is honored towards the downstream.</dd>
@@ -583,7 +583,40 @@ public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? ext
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
     public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources) {
-        return Flowable.fromIterable(sources).concatMapEager((Function)MaybeToPublisher.instance());
+        return Flowable.fromIterable(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), false);
+    }
+
+    /**
+     * Concatenates a sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence and
+     * runs a limited number of the inner sequences at once.
+     * <p>
+     * <img width="640" height="439" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEager.in.png" alt="">
+     * <p>
+     * Eager concatenation means that once an observer subscribes, this operator subscribes to all of the
+     * source {@code MaybeSource}s. The operator buffers the values emitted by these {@code MaybeSource}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource} that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code MaybeSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code MaybeSource}s can be active at the same time
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromIterable(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), false, maxConcurrency, 1);
     }
 
     /**
@@ -616,6 +649,173 @@ public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends
         return Flowable.fromPublisher(sources).concatMapEager((Function)MaybeToPublisher.instance());
     }
 
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence,
+     * running at most the given number of inner {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="425" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEager.pn.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code MaybeSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code MaybeSource}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code MaybeSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code MaybeSource}s can be active at the same time
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromPublisher(sources).concatMapEager((Function)MaybeToPublisher.instance(), maxConcurrency, 1);
+    }
+
+    /**
+     * Concatenates a sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence,
+     * delaying errors until all inner {@code MaybeSource}s terminate.
+     * <p>
+     * <img width="640" height="428" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEagerDelayError.i.png" alt="">
+     * <p>
+     * Eager concatenation means that once an observer subscribes, this operator subscribes to all of the
+     * source {@code MaybeSource}s. The operator buffers the values emitted by these {@code MaybeSource}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource} that need to be eagerly concatenated
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources) {
+        return Flowable.fromIterable(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), true);
+    }
+
+    /**
+     * Concatenates a sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence,
+     * delaying errors until all inner {@code MaybeSource}s terminate and
+     * runs a limited number of inner {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="379" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEagerDelayError.in.png" alt="">
+     * <p>
+     * Eager concatenation means that once an observer subscribes, this operator subscribes to all of the
+     * source {@code MaybeSource}s. The operator buffers the values emitted by these {@code MaybeSource}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource} that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code MaybeSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code MaybeSource}s can be active at the same time
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromIterable(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), true, maxConcurrency, 1);
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence,
+     * delaying errors until all the inner and the outer sequence terminate.
+     * <p>
+     * <img width="640" height="495" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEagerDelayError.p.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code MaybeSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code MaybeSource}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource}s that need to be eagerly concatenated
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources) {
+        return Flowable.fromPublisher(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), true);
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link MaybeSource}s eagerly into a {@link Flowable} sequence,
+     * delaying errors until all the inner and the outer sequence terminate and
+     * runs a limited number of the inner {@code MaybeSource}s at once.
+     * <p>
+     * <img width="640" height="421" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatEagerDelayError.pn.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code MaybeSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code MaybeSource}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code MaybeSource}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code MaybeSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code MaybeSource}s can be active at the same time
+     * @return the new {@code Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Publisher<@NonNull ? extends MaybeSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromPublisher(sources).concatMapEagerDelayError((Function)MaybeToPublisher.instance(), true, maxConcurrency, 1);
+    }
+
     /**
      * Provides an API (via a cold {@code Maybe}) that bridges the reactive world with the callback-style world.
      * <p>
diff --git a/src/main/java/io/reactivex/rxjava3/core/Observable.java b/src/main/java/io/reactivex/rxjava3/core/Observable.java
index 9eeb169871..033d12bdff 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Observable.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Observable.java
@@ -1460,14 +1460,70 @@ public static <T> Observable<T> concatDelayError(@NonNull ObservableSource<? ext
         return RxJavaPlugins.onAssembly(new ObservableConcatMap(sources, Functions.identity(), bufferSize, tillTheEnd ? ErrorMode.END : ErrorMode.BOUNDARY));
     }
 
+    /**
+     * Concatenates a sequence of {@link ObservableSource}s eagerly into a single stream of values.
+     * <p>
+     * <img width="640" height="422" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEager.i.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * {@code ObservableSource}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code ObservableSource}s that need to be eagerly concatenated
+     * @return the new {@code Observable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 2.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Observable<T> concatEager(@NonNull Iterable<@NonNull ? extends ObservableSource<? extends T>> sources) {
+        return concatEager(sources, bufferSize(), bufferSize());
+    }
+
+    /**
+     * Concatenates a sequence of {@link ObservableSource}s eagerly into a single stream of values and
+     * runs a limited number of inner sequences at once.
+     * <p>
+     * <img width="640" height="379" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEager.in.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * {@code ObservableSource}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them
+     * in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code ObservableSource}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code ObservableSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code ObservableSource}s can be active at the same time
+     * @param bufferSize the number of elements expected from each inner {@code ObservableSource} to be buffered
+     * @return the new {@code Observable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} or {@code bufferSize} is non-positive
+     * @since 2.0
+     */
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Observable<T> concatEager(@NonNull Iterable<@NonNull ? extends ObservableSource<? extends T>> sources, int maxConcurrency, int bufferSize) {
+        return fromIterable(sources).concatMapEagerDelayError((Function)Functions.identity(), false, maxConcurrency, bufferSize);
+    }
+
     /**
      * Concatenates an {@link ObservableSource} sequence of {@code ObservableSource}s eagerly into a single stream of values.
      * <p>
+     * <img width="640" height="495" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEager.o.png" alt="">
+     * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * emitted source {@code ObservableSource}s as they are observed. The operator buffers the values emitted by these
      * {@code ObservableSource}s and then drains them in order, each one after the previous one completes.
-     * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatEager.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1486,13 +1542,15 @@ public static <T> Observable<T> concatEager(@NonNull ObservableSource<? extends
     }
 
     /**
-     * Concatenates an {@link ObservableSource} sequence of {@code ObservableSource}s eagerly into a single stream of values.
+     * Concatenates an {@link ObservableSource} sequence of {@code ObservableSource}s eagerly into a single stream of values
+     * and runs a limited number of inner sequences at once.
+     * 
+     * <p>
+     * <img width="640" height="442" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEager.on.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * emitted source {@code ObservableSource}s as they are observed. The operator buffers the values emitted by these
      * {@code ObservableSource}s and then drains them in order, each one after the previous one completes.
-     * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatEager.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1516,13 +1574,14 @@ public static <T> Observable<T> concatEager(@NonNull ObservableSource<? extends
     }
 
     /**
-     * Concatenates a sequence of {@link ObservableSource}s eagerly into a single stream of values.
+     * Concatenates a sequence of {@link ObservableSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner sequences terminate.
+     * <p>
+     * <img width="640" height="428" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEagerDelayError.i.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * {@code ObservableSource}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them
      * in order, each one after the previous one completes.
-     * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatEager.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1531,23 +1590,25 @@ public static <T> Observable<T> concatEager(@NonNull ObservableSource<? extends
      * @param sources a sequence of {@code ObservableSource}s that need to be eagerly concatenated
      * @return the new {@code Observable} instance with the specified concatenation behavior
      * @throws NullPointerException if {@code sources} is {@code null}
-     * @since 2.0
+     * @since 3.0.0
      */
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public static <T> Observable<T> concatEager(@NonNull Iterable<@NonNull ? extends ObservableSource<? extends T>> sources) {
-        return concatEager(sources, bufferSize(), bufferSize());
+    public static <T> Observable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends ObservableSource<? extends T>> sources) {
+        return concatEagerDelayError(sources, bufferSize(), bufferSize());
     }
 
     /**
-     * Concatenates a sequence of {@link ObservableSource}s eagerly into a single stream of values.
+     * Concatenates a sequence of {@link ObservableSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner sequences terminate and runs a limited number of inner
+     * sequences at once.
+     * <p>
+     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEagerDelayError.in.png" alt="">
      * <p>
      * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
      * {@code ObservableSource}s. The operator buffers the values emitted by these {@code ObservableSource}s and then drains them
      * in order, each one after the previous one completes.
-     * <p>
-     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concatEager.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
@@ -1560,14 +1621,71 @@ public static <T> Observable<T> concatEager(@NonNull Iterable<@NonNull ? extends
      * @return the new {@code Observable} instance with the specified concatenation behavior
      * @throws NullPointerException if {@code sources} is {@code null}
      * @throws IllegalArgumentException if {@code maxConcurrency} or {@code bufferSize} is non-positive
-     * @since 2.0
+     * @since 3.0.0
      */
     @SuppressWarnings({ "unchecked", "rawtypes" })
     @CheckReturnValue
     @SchedulerSupport(SchedulerSupport.NONE)
     @NonNull
-    public static <T> Observable<T> concatEager(@NonNull Iterable<@NonNull ? extends ObservableSource<? extends T>> sources, int maxConcurrency, int bufferSize) {
-        return fromIterable(sources).concatMapEagerDelayError((Function)Functions.identity(), false, maxConcurrency, bufferSize);
+    public static <T> Observable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends ObservableSource<? extends T>> sources, int maxConcurrency, int bufferSize) {
+        return fromIterable(sources).concatMapEagerDelayError((Function)Functions.identity(), true, maxConcurrency, bufferSize);
+    }
+
+    /**
+     * Concatenates an {@link ObservableSource} sequence of {@code ObservableSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner and the outer sequence terminate.
+     * <p>
+     * <img width="640" height="496" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEagerDelayError.o.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code ObservableSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code ObservableSource}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code ObservableSource}s that need to be eagerly concatenated
+     * @return the new {@code Observable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Observable<T> concatEagerDelayError(@NonNull ObservableSource<? extends ObservableSource<? extends T>> sources) {
+        return concatEagerDelayError(sources, bufferSize(), bufferSize());
+    }
+
+    /**
+     * Concatenates an {@link ObservableSource} sequence of {@code ObservableSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner and the outer sequence terminate and runs a limited number of inner sequences at once.
+     * <p>
+     * <img width="640" height="421" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Observable.concatEagerDelayError.on.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code ObservableSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code ObservableSource}s and then drains them in order, each one after the previous one completes.
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code ObservableSource}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code ObservableSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code ObservableSource}s can be active at the same time
+     * @param bufferSize the number of inner {@code ObservableSource} expected to be buffered
+     * @return the new {@code Observable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} or {@code bufferSize} is non-positive
+     * @since 3.0.0
+     */
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @CheckReturnValue
+    @SchedulerSupport(SchedulerSupport.NONE)
+    @NonNull
+    public static <T> Observable<T> concatEagerDelayError(@NonNull ObservableSource<? extends ObservableSource<? extends T>> sources, int maxConcurrency, int bufferSize) {
+        return wrap(sources).concatMapEagerDelayError((Function)Functions.identity(), true, maxConcurrency, bufferSize);
     }
 
     /**
@@ -2923,7 +3041,7 @@ public static <T> Observable<T> just(@NonNull T item1, @NonNull T item2, @NonNul
      * @return the new {@code Observable} instance
      * @throws NullPointerException if {@code sources} is {@code null}
      * @throws IllegalArgumentException
-     *             if {@code maxConcurrent} or {@code bufferSize} is non-positive
+     *             if {@code maxConcurrency} or {@code bufferSize} is non-positive
      * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
      * @see #mergeDelayError(Iterable, int, int)
      */
@@ -2971,7 +3089,7 @@ public static <T> Observable<T> merge(@NonNull Iterable<@NonNull ? extends Obser
      * @return the new {@code Observable} instance
      * @throws NullPointerException if {@code sources} is {@code null}
      * @throws IllegalArgumentException
-     *             if {@code maxConcurrent} or {@code bufferSize} is non-positive
+     *             if {@code maxConcurrency} or {@code bufferSize} is non-positive
      * @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
      * @see #mergeArrayDelayError(int, int, ObservableSource...)
      */
diff --git a/src/main/java/io/reactivex/rxjava3/core/Single.java b/src/main/java/io/reactivex/rxjava3/core/Single.java
index 667125b08b..09c67ef5a1 100644
--- a/src/main/java/io/reactivex/rxjava3/core/Single.java
+++ b/src/main/java/io/reactivex/rxjava3/core/Single.java
@@ -492,35 +492,6 @@ public static <T> Flowable<T> concatArrayEagerDelayError(@NonNull SingleSource<?
         return Flowable.fromArray(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), true);
     }
 
-    /**
-     * Concatenates a {@link Publisher} sequence of {@link SingleSource}s eagerly into a single stream of values.
-     * <p>
-     * <img width="640" height="307" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEager.p.png" alt="">
-     * <p>
-     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
-     * emitted source {@code SingleSource}s as they are observed. The operator buffers the values emitted by these
-     * {@code SingleSource}s and then drains them in order, each one after the previous one succeeds.
-     * <dl>
-     *  <dt><b>Backpressure:</b></dt>
-     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
-     *  expected to support backpressure. Violating this assumption, the operator will
-     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
-     *  <dt><b>Scheduler:</b></dt>
-     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
-     * </dl>
-     * @param <T> the value type
-     * @param sources a sequence of {@code SingleSource}s that need to be eagerly concatenated
-     * @return the new {@link Flowable} instance with the specified concatenation behavior
-     * @throws NullPointerException if {@code sources} is {@code null}
-     */
-    @BackpressureSupport(BackpressureKind.FULL)
-    @CheckReturnValue
-    @NonNull
-    @SchedulerSupport(SchedulerSupport.NONE)
-    public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
-        return Flowable.fromPublisher(sources).concatMapEager(SingleInternalHelper.toFlowable());
-    }
-
     /**
      * Concatenates the {@link Iterable} sequence of {@link SingleSource}s into a single sequence by subscribing to each {@code SingleSource},
      * one after the other, one at a time and delays any errors till the all inner {@code SingleSource}s terminate
@@ -631,7 +602,228 @@ public static <T> Flowable<T> concatDelayError(@NonNull Publisher<@NonNull ? ext
     @NonNull
     @SchedulerSupport(SchedulerSupport.NONE)
     public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources) {
-        return Flowable.fromIterable(sources).concatMapEager(SingleInternalHelper.toFlowable());
+        return Flowable.fromIterable(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), false);
+    }
+
+    /**
+     * Concatenates an {@link Iterable} sequence of {@link SingleSource}s eagerly into a single stream of values and
+     * runs a limited number of the inner sources at once.
+     * <p>
+     * <img width="640" height="439" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEager.in.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * source {@code SingleSource}s. The operator buffers the values emitted by these {@code SingleSource}s and then drains them
+     * in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources an {@code Iterable} sequence of {@code SingleSource} that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code SingleSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code SingleSource}s can be active at the same time
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEager(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromIterable(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), false, maxConcurrency, 1);
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link SingleSource}s eagerly into a single stream of values.
+     * <p>
+     * <img width="640" height="307" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEager.p.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code SingleSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code SingleSource}s and then drains them in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code SingleSource}s that need to be eagerly concatenated
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
+        return Flowable.fromPublisher(sources).concatMapEager(SingleInternalHelper.toFlowable());
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link SingleSource}s eagerly into a single stream of values and
+     * runs a limited number of those inner {@code SingleSource}s at once.
+     * <p>
+     * <img width="640" height="425" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEager.pn.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code SingleSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code SingleSource}s and then drains them in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code SingleSource}s that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code SingleSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code SingleSource}s can be active at the same time
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEager(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromPublisher(sources).concatMapEager(SingleInternalHelper.toFlowable(), maxConcurrency, 1);
+    }
+
+    /**
+     * Concatenates an {@link Iterable} sequence of {@link SingleSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner sources terminate.
+     * <p>
+     * <img width="640" height="431" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEagerDelayError.i.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * source {@code SingleSource}s. The operator buffers the values emitted by these {@code SingleSource}s and then drains them
+     * in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources an {@code Iterable} sequence of {@code SingleSource} that need to be eagerly concatenated
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources) {
+        return Flowable.fromIterable(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), true);
+    }
+
+    /**
+     * Concatenates an {@link Iterable} sequence of {@link SingleSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner sources terminate.
+     * <p>
+     * <img width="640" height="378" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEagerDelayError.in.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * source {@code SingleSource}s. The operator buffers the values emitted by these {@code SingleSource}s and then drains them
+     * in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources an {@code Iterable} sequence of {@code SingleSource} that need to be eagerly concatenated
+     * @param maxConcurrency the maximum number of concurrently running inner {@code SingleSource}s; {@link Integer#MAX_VALUE}
+     *                       is interpreted as all inner {@code SingleSource}s can be active at the same time
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Iterable<@NonNull ? extends SingleSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromIterable(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), true, maxConcurrency, 1);
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link SingleSource}s eagerly into a single stream of values,
+     * delaying errors until all the inner and the outer sequence terminate.
+     * <p>
+     * <img width="640" height="444" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEagerDelayError.p.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code SingleSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code SingleSource}s and then drains them in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code SingleSource}s that need to be eagerly concatenated
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources) {
+        return Flowable.fromPublisher(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), true);
+    }
+
+    /**
+     * Concatenates a {@link Publisher} sequence of {@link SingleSource}s eagerly into a single stream of values,
+     * running at most the specified number of those inner {@code SingleSource}s at once and
+     * delaying errors until all the inner and the outer sequence terminate.
+     * <p>
+     * <img width="640" height="421" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatEagerDelayError.pn.png" alt="">
+     * <p>
+     * Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
+     * emitted source {@code SingleSource}s as they are observed. The operator buffers the values emitted by these
+     * {@code SingleSource}s and then drains them in order, each one after the previous one succeeds.
+     * <dl>
+     *  <dt><b>Backpressure:</b></dt>
+     *  <dd>Backpressure is honored towards the downstream and the outer {@code Publisher} is
+     *  expected to support backpressure. Violating this assumption, the operator will
+     *  signal {@link io.reactivex.rxjava3.exceptions.MissingBackpressureException}.</dd>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param <T> the value type
+     * @param sources a sequence of {@code SingleSource}s that need to be eagerly concatenated
+     * @param maxConcurrency the number of inner {@code SingleSource}s to run at once
+     * @return the new {@link Flowable} instance with the specified concatenation behavior
+     * @throws NullPointerException if {@code sources} is {@code null}
+     * @throws IllegalArgumentException if {@code maxConcurrency} is non-positive
+     * @since 3.0.0
+     */
+    @BackpressureSupport(BackpressureKind.FULL)
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public static <T> Flowable<T> concatEagerDelayError(@NonNull Publisher<@NonNull ? extends SingleSource<? extends T>> sources, int maxConcurrency) {
+        return Flowable.fromPublisher(sources).concatMapEagerDelayError(SingleInternalHelper.toFlowable(), true, maxConcurrency, 1);
     }
 
     /**
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapEagerTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapEagerTest.java
index 0adfd655b0..b8c2eaaff3 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapEagerTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableConcatMapEagerTest.java
@@ -744,7 +744,7 @@ public void Flowable() {
     }
 
     @Test
-    public void ObservableCapacityHint() {
+    public void publisherCapacityHint() {
         Flowable<Integer> source = Flowable.just(1);
         TestSubscriber<Integer> ts = TestSubscriber.create();
 
@@ -1351,4 +1351,48 @@ public Flowable<Integer> apply(Integer v) throws Throwable {
             }
         });
     }
+
+    @Test
+    public void iterableDelayError() {
+        Flowable.concatEagerDelayError(Arrays.asList(
+                Flowable.range(1, 2),
+                Flowable.error(new TestException()),
+                Flowable.range(3, 3)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
+
+    @Test
+    public void iterableDelayErrorMaxConcurrency() {
+        Flowable.concatEagerDelayError(Arrays.asList(
+                Flowable.range(1, 2),
+                Flowable.error(new TestException()),
+                Flowable.range(3, 3)
+        ), 1, 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
+
+    @Test
+    public void publisherDelayError() {
+        Flowable.concatEagerDelayError(Flowable.fromArray(
+                Flowable.range(1, 2),
+                Flowable.error(new TestException()),
+                Flowable.range(3, 3)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
+
+    @Test
+    public void publisherDelayErrorMaxConcurrency() {
+        Flowable.concatEagerDelayError(Flowable.fromArray(
+                Flowable.range(1, 2),
+                Flowable.error(new TestException()),
+                Flowable.range(3, 3)
+        ), 1, 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatEagerTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatEagerTest.java
new file mode 100644
index 0000000000..5a1b42bb15
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/maybe/MaybeConcatEagerTest.java
@@ -0,0 +1,152 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.maybe;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class MaybeConcatEagerTest {
+
+    @Test
+    public void iterableNormal() {
+        Maybe.concatEager(Arrays.asList(
+                Maybe.just(1),
+                Maybe.empty(),
+                Maybe.just(2)
+        ))
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void iterableNormalMaxConcurrency() {
+        Maybe.concatEager(Arrays.asList(
+                Maybe.just(1),
+                Maybe.empty(),
+                Maybe.just(2)
+        ), 1)
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void iterableError() {
+        Maybe.concatEager(Arrays.asList(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void iterableErrorMaxConcurrency() {
+        Maybe.concatEager(Arrays.asList(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void publisherNormal() {
+        Maybe.concatEager(Flowable.fromArray(
+                Maybe.just(1),
+                Maybe.empty(),
+                Maybe.just(2)
+        ))
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void publisherNormalMaxConcurrency() {
+        Maybe.concatEager(Flowable.fromArray(
+                Maybe.just(1),
+                Maybe.empty(),
+                Maybe.just(2)
+        ), 1)
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void publisherError() {
+        Maybe.concatEager(Flowable.fromArray(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void iterableDelayError() {
+        Maybe.concatEagerDelayError(Arrays.asList(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void iterableDelayErrorMaxConcurrency() {
+        Maybe.concatEagerDelayError(Arrays.asList(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void publisherDelayError() {
+        Maybe.concatEagerDelayError(Flowable.fromArray(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void publisherDelayErrorMaxConcurrency() {
+        Maybe.concatEagerDelayError(Flowable.fromArray(
+                Maybe.just(1),
+                Maybe.error(new TestException()),
+                Maybe.empty(),
+                Maybe.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableConcatMapEagerTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableConcatMapEagerTest.java
index e13124bf5d..054ab91d8f 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableConcatMapEagerTest.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableConcatMapEagerTest.java
@@ -1034,4 +1034,48 @@ public Observable<Integer> apply(Integer v) throws Throwable {
             }
         });
     }
+
+    @Test
+    public void iterableDelayError() {
+        Observable.concatEagerDelayError(Arrays.asList(
+                Observable.range(1, 2),
+                Observable.error(new TestException()),
+                Observable.range(3, 3)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
+
+    @Test
+    public void iterableDelayErrorMaxConcurrency() {
+        Observable.concatEagerDelayError(Arrays.asList(
+                Observable.range(1, 2),
+                Observable.error(new TestException()),
+                Observable.range(3, 3)
+        ), 1, 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
+
+    @Test
+    public void observerDelayError() {
+        Observable.concatEagerDelayError(Observable.fromArray(
+                Observable.range(1, 2),
+                Observable.error(new TestException()),
+                Observable.range(3, 3)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
+
+    @Test
+    public void observerDelayErrorMaxConcurrency() {
+        Observable.concatEagerDelayError(Observable.fromArray(
+                Observable.range(1, 2),
+                Observable.error(new TestException()),
+                Observable.range(3, 3)
+        ), 1, 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2, 3, 4, 5);
+    }
 }
diff --git a/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatEagerTest.java b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatEagerTest.java
new file mode 100644
index 0000000000..c21c5347d4
--- /dev/null
+++ b/src/test/java/io/reactivex/rxjava3/internal/operators/single/SingleConcatEagerTest.java
@@ -0,0 +1,141 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.internal.operators.single;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
+
+public class SingleConcatEagerTest {
+
+    @Test
+    public void iterableNormal() {
+        Single.concatEager(Arrays.asList(
+                Single.just(1),
+                Single.just(2)
+        ))
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void iterableNormalMaxConcurrency() {
+        Single.concatEager(Arrays.asList(
+                Single.just(1),
+                Single.just(2)
+        ), 1)
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void iterableError() {
+        Single.concatEager(Arrays.asList(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void iterableErrorMaxConcurrency() {
+        Single.concatEager(Arrays.asList(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void publisherNormal() {
+        Single.concatEager(Flowable.fromArray(
+                Single.just(1),
+                Single.just(2)
+        ))
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void publisherNormalMaxConcurrency() {
+        Single.concatEager(Flowable.fromArray(
+                Single.just(1),
+                Single.just(2)
+        ), 1)
+        .test()
+        .assertResult(1, 2);
+    }
+
+    @Test
+    public void publisherError() {
+        Single.concatEager(Flowable.fromArray(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1);
+    }
+
+    @Test
+    public void iterableDelayError() {
+        Single.concatEagerDelayError(Arrays.asList(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void iterableDelayErrorMaxConcurrency() {
+        Single.concatEagerDelayError(Arrays.asList(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void publisherDelayError() {
+        Single.concatEagerDelayError(Flowable.fromArray(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ))
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+
+    @Test
+    public void publisherDelayErrorMaxConcurrency() {
+        Single.concatEagerDelayError(Flowable.fromArray(
+                Single.just(1),
+                Single.error(new TestException()),
+                Single.just(2)
+        ), 1)
+        .test()
+        .assertFailure(TestException.class, 1, 2);
+    }
+}
diff --git a/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java b/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java
index 5c0886ea9d..aa388a684a 100644
--- a/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java
+++ b/src/test/java/io/reactivex/rxjava3/internal/util/MarbleDimensions.java
@@ -98,7 +98,7 @@ public static void main(String[] args) throws Throwable {
         }
     }
 
-    static final int SLEEP_PER_IMAGE_MILLIS = 100;
+    static final int SLEEP_PER_IMAGE_MILLIS = 25;
 
     static final Class<?>[] CLASSES = {
             Flowable.class, Observable.class, Maybe.class, Single.class, Completable.class, ParallelFlowable.class
diff --git a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
index 2ce716e342..0445bfbe71 100644
--- a/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
+++ b/src/test/java/io/reactivex/rxjava3/validators/ParamValidationNaming.java
@@ -527,6 +527,7 @@ static final class ValidatorStrings {
             new ValidatorStrings("itemDelayIndicator", "* @throws NullPointerException"),
             new ValidatorStrings("future", "* @throws NullPointerException"),
 
+            new ValidatorStrings("maxConcurrency", "* @throws IllegalArgumentException"),
             new ValidatorStrings("parallelism", "* @throws IllegalArgumentException"),
             new ValidatorStrings("prefetch", "* @throws IllegalArgumentException"),
             new ValidatorStrings("bufferSize", "* @throws IllegalArgumentException"),