code: func NewRateLimitedSMSService(window int, maxSMS int, actualService SMSService) SMSService {
  	return &RateLimitedSMSService{
  		actualService: actualService,
  		window:        time.Duration(int(time.Second) * window),
  		maxSMS:        maxSMS,
  	}
  }
docs: // NewRateLimitedSMSService rates limit an existing sms service to the defined rate