public void notifyListeners(InstanceEvent event) {
   if (event.getType() == InstanceEventType.INSTANCE_ABOUT_TO_TRANSITION) {
     fireInstanceAboutToTransition(event);
   } else {
     eventsToFire.add(event);
     synchronized (eventsToFire) {
       eventsToFire.notify();
     }
   }
 }
 public void removeInstanceListener(IInstanceListener listener) {
   removeListenerObject(listener);
   synchronized (eventsToFire) {
     eventsToFire.notify();
   }
 }