anchor.diff:    /// 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 id of the isolate group that this isolate belongs to.
  +  String? isolateGroupId;
   
     /// The list of isolate flags provided to this isolate. See Dart_IsolateFlags
     /// in dart_api.h for the list of accepted isolate flags.
  
positive.code:       'number': number,
        'name': name,
        'isSystemIsolate': isSystemIsolate,
        'isolateFlags': isolateFlags?.map((f) => f.toJson()).toList(),
        'startTime': startTime,
        'runnable': runnable,
  
negative.code:         HeapSnapshotObjectNoData,
          HeapSnapshotObjectNullData;
  
  const String vmServiceVersion = '3.61.0';
  
  /// @optional
  const String optional = 'optional';
  