code: func (api *Client) SetUserCustomStatus(statusText, statusEmoji string, statusExpiration int64) error {
  	return api.SetUserCustomStatusContext(context.Background(), statusText, statusEmoji, statusExpiration)
  }
docs: // SetUserCustomStatus will set a custom status and emoji for the currently
  // authenticated user. If statusEmoji is "" and statusText is not, the Slack API
  // will automatically set it to ":speech_balloon:". Otherwise, if both are ""
  // the Slack API will unset the custom status/emoji. If statusExpiration is set to 0
  // the status will not expire.