addObserver method
Registers a consumer to observe changes on this node.
Implementation
@override
void addObserver(Consumer consumer) {
final shouldTriggerListen = isDisposed || !_hasBeenObserved;
if (isDisposed) {
isDisposed = false;
}
_hasBeenObserved = true;
super.addObserver(consumer);
if (shouldTriggerListen) {
onListenCallback?.call();
}
}