docs: public void close()	{
  		if (watchdog != null) {
  			watchdog.cancel();
  			watchdog = null;
  		}
  		
  		disconnect();
  		
  		// clear nodes collection and send queue
  		for (Object listener : this.zwaveEventListeners.toArray()) {
  			if (!(listener instanceof ZWaveNode))
  				continue;
  			
  			this.zwaveEventListeners.remove(listener);
  		}
  		
  		this.zwaveNodes.clear();
  		this.sendQueue.clear();
  		
  		logger.info("Stopped Z-Wave controller");
  	}