code: func (task *Task) SetExecutionStoppedAt(timestamp time.Time) bool {
  	task.lock.Lock()
  	defer task.lock.Unlock()
  
  	if task.ExecutionStoppedAtUnsafe.IsZero() {
  		task.ExecutionStoppedAtUnsafe = timestamp
  		return true
  	}
  	return false
  }
docs: // SetExecutionStoppedAt sets the ExecutionStoppedAt timestamp of the task