code: @SuppressWarnings("unchecked")
      public <E> MessageHandler<? super E> removeReceivedMessageHandler(Class<E> type) {
          receivedMessageHandlerCache.clear();
          return (MessageHandler<? super E>) receivedMessageHandlers.remove(type);
      }
docs: Deregisters a {@link MessageHandler} that handles the received messages
  of the specified <code>type</code>.
  
  @return the removed handler if successfully removed.  <tt>null</tt> otherwise.