anchor.diff:  
     _TravelingTimer({
       required _FakeTime owner,
  -    required DateTime createdInOriginalTime,
       required DateTime createdInFakeTime,
       required ZoneDelegate parent,
       required Zone zone,
       required Duration duration,
       required void Function() trigger,
     })  : _owner = owner,
  -        _createdInOriginalTime = createdInOriginalTime,
           _createdInFakeTime = createdInFakeTime,
           _parent = parent,
           _zone = zone,
  
positive.code:   final _FakeTime _owner;
  
    /// [DateTime] when this [_TravelingTimer] was created in
    /// [_FakeTime._originalTime].
    final DateTime _createdInOriginalTime;
  
    /// [DateTime] when this [_TravelingTimer] was created in
    /// [_FakeTime._fakeTime].
    final DateTime _createdInFakeTime;
  
  
negative.code:   ) {
      final timer = _TravelingTimer.periodic(
        owner: this,
        createdInFakeTime: _fakeTime(),
        parent: parent,
        zone: zone,
  