code: public <T> int getRegisteredEventListeners(Class<T> type, Collection<? super T> collection) {
  		synchronized (this.behaviorGuardEvaluatorRegistry) {
  			return this.behaviorGuardEvaluatorRegistry.getRegisteredEventListeners(type, collection);
  		}
  	}
docs: Extract the registered listeners with the given type.
  
  @param <T> the type of the listeners.
  @param type the type of the listeners.
  @param collection the collection of listeners that is filled by this function.
  @return the number of listeners added to the collection.
  @since 0.5