code: public void sendTo(String topicURI, Object event,
  			Set<String> eligibleWebSocketSessionIds) {
  		EventMessage eventMessage = new EventMessage(topicURI, event);
  		eventMessage.setEligibleWebSocketSessionIds(eligibleWebSocketSessionIds);
  		send(eventMessage);
  	}
docs: Send an {@link EventMessage} to every client that is currently subscribed to the
  given topicURI and is listed in the eligibleSessionIds set. If no session of the
  provided set is subscribed to the topicURI nothing happens.
  
  @param topicURI the name of the topic
  @param event the payload of the {@link EventMessage}
  @param eligibleWebSocketSessionIds only the WebSocket session ids listed here will
  receive the EVENT message. If null or empty nobody receives the message.