code: func (mq *MessageQuery) QuickReply(qr QuickReply) error {
  	//max 10 quick replies
  	if len(mq.Message.QuickReplies) >= 10 {
  		return errors.New("Number of quick replies is limited to 10")
  	}
  
  	//if location then no title or payload
  	if qr.ContentType == ContentTypeLocation && (len(qr.Title) != 0 || len(qr.Payload) != 0) {
  		return errors.New("Location ContentType supports neither title nor payload")
  	}
  
  	//title has a 20 character limit
  	if len(qr.Title) > 20 {
  		return errors.New("Title is too long, it has a 20 character limit.")
  	}
  	//payload has a 1000 character limit
  	if len(qr.Payload) > 1000 {
  		return errors.New("Payload is too long, it has a 1000 character limit.")
  	}
  
  	if len(qr.ContentType) == 0 {
  		qr.ContentType = ContentTypeText
  	}
  
  	mq.Message.QuickReplies = append(mq.Message.QuickReplies, qr)
  	return nil
  }
docs: // Documentation: https://developers.facebook.com/docs/messenger-platform/send-api-reference/quick-replies#quick_reply