TimelineTask.withTaskId(int taskId, {String category: 'Dart'})

Create a task with an explicit taskId. This is useful if you are passing a task between isolates. Optionally you can specify a category name.

Source

TimelineTask.withTaskId(int taskId, {String category: 'Dart'})
    : _taskId = taskId,
      category = category {
  if (taskId is! int) {
    throw new ArgumentError.value(taskId,
                                  'taskId',
                                  'Must be an int');
  }
  if (category is! String) {
    throw new ArgumentError.value(category,
                                  'category',
                                  'Must be a String');
  }
}