code: protected void fireReferenceRelease(int released) {
  		final List<ReferenceListener> list = this.listeners;
  		if (list != null && !list.isEmpty()) {
  			for (final ReferenceListener listener : list) {
  				listener.referenceReleased(released);
  			}
  		}
  	}
docs: Fire the reference release event.
  
  @param released is the count of released objects.