public void messageArrived(MqttPublish sendMessage) {
		final String methodName = "messageArrived";
		if (mqttCallback != null || !callbacksWildcards.isEmpty() || !callbacksDirect.isEmpty()) {
			// If we already have enough messages queued up in memory, wait
			// until some more queue space becomes available. This helps 
			// the client protect itself from getting flooded by messages 
			// from the server.
			synchronized (spaceAvailable) {
				while (isRunning() && !isQuiescing() && messageQueue.size() >= INBOUND_QUEUE_SIZE) { 
					try {
						// @TRACE 709=wait for spaceAvailable
						log.fine(CLASS_NAME, methodName, "709");
						spaceAvailable.wait(200);
					} catch (InterruptedException ex) {
					}
				}
			}
			if (!isQuiescing()) {
				messageQueue.addElement(sendMessage);
				// Notify the CommsCallback thread that there's work to do...
				synchronized (workAvailable) {
					// @TRACE 710=new msg avail, notify workAvailable
					log.fine(CLASS_NAME, methodName, "710");
					workAvailable.notifyAll();
				}
			}
		}
	}