anchor.diff:      this.number,
       this.name,
       this.isSystemIsolate,
  +    this.isolateGroupId,
       this.isolateFlags,
       this.startTime,
       this.runnable,
  
positive.code:   /// Specifies whether the isolate was spawned by the VM or embedder for
    /// internal use. If `false`, this isolate is likely running user code.
    bool? isSystemIsolate;
  
    /// The list of isolate flags provided to this isolate. See Dart_IsolateFlags
    /// in dart_api.h for the list of accepted isolate flags.
  
negative.code:     number = json['number'] ?? '';
      name = json['name'] ?? '';
      isSystemIsolate = json['isSystemIsolate'] ?? false;
      isolateGroupId = json['isolateGroupId'] ?? '';
    }
  
    @override
  