Buffer with Observable boundary.

[akarnokd]

Mentined in Issue #653.

• 1 overload where the user can specify the capacity of the internal buffer.

[cloudbees-pull-request-builder]

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[zsxwing]

observer.onNext, onCompleted, onError can be called from different Observables, so I suppose we need to wrap it by a SynchronizedObserver.

[akarnokd]

Observer is mostly used from the boundary observable but we can move the onXXX functions into the guard block.

[zsxwing]

According to Rx contract, I think all operators should support the following observer.

        Observer<Integer> o = new Observer<Integer>() {
            private int count = 0;

            @Override
            public void onCompleted() {
                count++;
            }

            @Override
            public void onError(Throwable e) {
                count++;
            }

            @Override
            public void onNext(Integer args) {
                count++;
            }
        };

[benjchristensen]

That's correct.