anchor.diff:      bool Function(Uint8List element) test, {
       List<int> Function() orElse,
     }) {
  -    return _delegate.firstWhere(test, orElse: orElse);
  +    return _delegate.firstWhere(test, orElse: () {
  +      return Uint8List.fromList(orElse());
  +    });
     }
   
     @override
  
positive.code: 
    @override
    Future<Uint8List> singleWhere(bool Function(Uint8List element) test, {List<int> Function() orElse}) {
      return _delegate.singleWhere(test, orElse: orElse);
    }
  
    @override
  
negative.code:     bool Function(Uint8List element) test, {
      List<int> Function() orElse,
    }) {
      return _delegate.lastWhere(test, orElse: () {
        return Uint8List.fromList(orElse());
      });
    }
  
    @override
  