void notifyEnded(HandGrab.Direction a, Vector3 b)
 {
     Log("notifyEnded");
     foreach (HandGrabEndedEvent trackedEvent in _handGestureGrabEndedEvent)
     {
         trackedEvent.Invoke(a, b);
     }
 }
 void notifyMoved(HandGrab.Direction a, Vector3 b, Vector3 c)
 {
     Log("notifyMoved");
     foreach (HandGrabMovedEvent trackedEvent in _handGestureGrabMovedEvent)
     {
         trackedEvent.Invoke(a, b, c);
     }
 }