code: func (w *Webhook) SendLinkMsg(title, content, picURL, msgURL string) error {
  	return w.SendPayload(&Payload{
  		MsgType: "link",
  		Link: struct {
  			Text       string `json:"text"`
  			Title      string `json:"title"`
  			PicURL     string `json:"picUrl"`
  			MessageURL string `json:"messageUrl"`
  		}{
  			Text:       content,
  			Title:      title,
  			PicURL:     picURL,
  			MessageURL: msgURL,
  		},
  	})
  }
docs: // SendLinkMsg 发送链接消息