attachNotificationTree method
Called in Element.mount and Element.activate to register this element in the notification tree.
This method is only exposed so that NotifiableElementMixin can be implemented. Subclasses of Element that wish to respond to notifications should mix that in instead.
See also:
- NotificationListener, a widget that allows listening to notifications.
Implementation
@protected
void attachNotificationTree() {
_notificationTree = _parent?._notificationTree;
}