| located | Set to true if the object is locatable. |
| self | The WorldAnchor reporting the tracking state change. |
Event that is fired when this object's tracking state changes.
By default, when an object loses its ability to be tracked it will be deactivated. This behavior can be overridden by listening for this event. If this event is subscribed to it is up to to the developer to handle loss of tracking state for this object.