anchor.diff:  // Copyright 2014 The Flutter Authors. All rights reserved.
   // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
  -
  -// @dart = 2.8
   
   import 'dart:async';
   import 'dart:collection';
  
positive.code:   T get<T>() {
      dynamic value = _generateIfNecessary(T, _overrides);
      if (value == null && _parent != null) {
        value = _parent.get<T>();
      }
      return _unboxNull(value ?? _generateIfNecessary(T, _fallbacks)) as T;
    }
  
negative.code:   /// name. This is useful for debugging purposes and is analogous to naming a
    /// thread in Java.
    Future<V> run<V>({
      required FutureOr<V> Function() body,
      String? name,
      Map<Type, Generator>? overrides,
      Map<Type, Generator>? fallbacks,
      ZoneSpecification? zoneSpecification,
    }) async {
      final AppContext child = AppContext._(
        this,
  