docs: public List getReceivers() {
  		ArrayList result = new ArrayList();
  		synchronized (attributes) {
  			Iterator i = attributes.values().iterator();
  			while (i.hasNext()) {
  				Object o = i.next();
  				if (o instanceof ReceiverQueue) {
  					result.add(o);
  				}
  			}
  		}
  		return result;
  	}