code: func checkPort(host string, port int) error {
  	log.Trace("Verifying remote TCP connectivity", "server", host, "port", port)
  	conn, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", host, port), time.Second)
  	if err != nil {
  		return err
  	}
  	conn.Close()
  	return nil
  }
docs: // checkPort tries to connect to a remote host on a given