Add getThreadPool() method to return current thread pool used.

Author: Oriental Sensation

library/src/main/java/com/loopj/android/http/AsyncHttpClient.java

@@ -338,6 +338,16 @@ public void setThreadPool(ThreadPoolExecutor threadPool) {
         this.threadPool = threadPool;
     }
 
+    /**
+     * Returns the current executor service used. By default,
+     * Executors.newFixedThreadPool() is used.
+     *
+     * @return current executor service used
+     */
+    public ExecutorService getThreadPool() {
+        return threadPool;
+    }
+
     /**
      * Simple interface method, to enable or disable redirects. If you set manually RedirectHandler
      * on underlying HttpClient, effects of this method will be canceled.