anchor.diff:  // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
   
  -// @dart=2.9
  +// ignore_for_file: import_of_legacy_library_into_null_safe
   
   import 'package:flutter/foundation.dart';
   import 'package:vm_service/vm_service.dart';
  
positive.code:   }
  
    void _handleStdoutEvent(Event event) {
      final String text = decodeBase64(event.bytes);
      appendStdio(text);
    }
  
    void _handleStderrEvent(Event event) {
      final String text = decodeBase64(event.bytes);
      // TODO(devoncarew): Change to reporting stdio along with information about
      // whether the event was stdout or stderr.
      appendStdio(text);
  
negative.code:   final _stdio = ListValueNotifier<ConsoleLine>([]);
    bool _stdioTrailingNewline = false;
  
    ObjectGroupBase? get objectGroup {
      final inspectorService = serviceManager.inspectorService;
      if (_objectGroup?.inspectorService == inspectorService) {
        return _objectGroup;
      }
      _objectGroup?.dispose();
      _objectGroup = inspectorService.createObjectGroup('console');
      return _objectGroup;
    }
  
    ObjectGroupBase? _objectGroup;
  
    /// Clears the contents of stdio.
    void clearStdio() {
      if (_stdio.value.isNotEmpty) {
        _stdio.clear();
      }
    }
  