code: func (btn *Button) SetMediaIDButton(name, mediaID string) {
  	btn.Type = "media_id"
  	btn.Name = name
  	btn.MediaID = mediaID
  
  	btn.Key = ""
  	btn.URL = ""
  	btn.SubButtons = nil
  }
docs: //SetMediaIDButton  设置 下发消息(除文本消息) 类型按钮