code: func (t *servingTask) waitOrStop() bool {
  	t.done()
  	if !t.biasAdded {
  		t.priority += t.sq.suspendBias
  		t.biasAdded = true
  	}
  	return t.start()
  }
docs: // waitOrStop can be called during the execution of the task. It blocks if there
  // is a higher priority task waiting (a bias is applied in favor of the currently
  // running task). Returning true means that the execution can be resumed. False
  // means the task should be cancelled.