anchor.diff:      _playerEditor = null;
   
       if (_lifecycleObserver != null) {
  -      WidgetsBinding.instance?.removeObserver(_lifecycleObserver!);
  +      WidgetsBinding.instance.removeObserver(_lifecycleObserver!);
         _lifecycleObserver = null;
       }
     }
  
positive.code: import 'package:flutter/services.dart';
  import 'package:path_provider/path_provider.dart';
  import 'package:rxdart/rxdart.dart';
  import 'package:rxdart/subjects.dart';
  import 'package:uuid/uuid.dart';
  
  import 'applifecycle.dart';
  
negative.code:       }
      });
      if (_lifecycleObserver != null) {
        WidgetsBinding.instance.addObserver(_lifecycleObserver!);
      }
    }
  
  