code: @Override
  	public void receiveHeartbeat(ResourceID heartbeatOrigin, I heartbeatPayload) {
  		if (!stopped) {
  			log.debug("Received heartbeat from {}.", heartbeatOrigin);
  			reportHeartbeat(heartbeatOrigin);
  
  			if (heartbeatPayload != null) {
  				heartbeatListener.reportPayload(heartbeatOrigin, heartbeatPayload);
  			}
  		}
  	}
docs: ----------------------------------------------------------------------------------------------