list.dart

class MyListNotifier extends ValueNotifier<MyList> {
  MyListNotifier(MyList myList) : super(myList) {
    value.setNotifyListeners(notifyListeners);
  }
}

class MyList<E> extends List<E> {
  VoidCallback _notifyListeners;
  void setNotifyListeners(VoidCallback notifyListeners) {
    this.notifyListeners = notifyListeners;
  }

  @override
  void add(E element) {
    super.add(element);
    _notifyListeners();
  }
  
  // etc for needed mutating methods
}