code: func NewQueue(service *Service, workers uint) *Queue {
  	// unbuffered channels
  	q := &Queue{
  		service:       service,
  		notifications: make(chan notification),
  		Responses:     make(chan Response),
  	}
  	// startup workers to send notifications
  	for i := uint(0); i < workers; i++ {
  		go worker(q)
  	}
  	return q
  }
docs: // NewQueue wraps a service with a queue for sending notifications asynchronously.