code: public Observable<CloudTaskListSubtasksResult> listSubtasksAsync(String jobId, String taskId, TaskListSubtasksOptions taskListSubtasksOptions) {
          return listSubtasksWithServiceResponseAsync(jobId, taskId, taskListSubtasksOptions).map(new Func1<ServiceResponseWithHeaders<CloudTaskListSubtasksResult, TaskListSubtasksHeaders>, CloudTaskListSubtasksResult>() {
              @Override
              public CloudTaskListSubtasksResult call(ServiceResponseWithHeaders<CloudTaskListSubtasksResult, TaskListSubtasksHeaders> response) {
                  return response.body();
              }
          });
      }
docs: Lists all of the subtasks that are associated with the specified multi-instance task.
  If the task is not a multi-instance task then this returns an empty collection.
  
  @param jobId The ID of the job.
  @param taskId The ID of the task.
  @param taskListSubtasksOptions Additional parameters for the operation
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CloudTaskListSubtasksResult object