import 'package:flutter/foundation.dart'; // ignore: prefer_void_to_null class _RebuildNode implements ValueListenable { final List _listeners = []; _RebuildNode(); @override void addListener(VoidCallback listener) { _listeners.add(listener); } @override void removeListener(VoidCallback listener) { _listeners.remove(listener); } void rebuild() { for (var listener in _listeners) { listener(); } } @override Null get value => null; } class RebuildNodes { const RebuildNodes._(); static final _RebuildNode app = _RebuildNode(); }