code: func SetTCPOptions(conn net.Conn) error {
  	switch conn := conn.(type) {
  	case *net.TCPConn:
  		var err error
  		if err = conn.SetLinger(0); err != nil {
  			return err
  		}
  		if err = conn.SetNoDelay(false); err != nil {
  			return err
  		}
  		if err = conn.SetKeepAlivePeriod(60 * time.Second); err != nil {
  			return err
  		}
  		if err = conn.SetKeepAlive(true); err != nil {
  			return err
  		}
  		return nil
  
  	case dialerConn:
  		return SetTCPOptions(conn.Conn)
  
  	default:
  		return fmt.Errorf("unknown connection type %T", conn)
  	}
  }
docs: // SetTCPOptions sets our default TCP options on a TCP connection, possibly
  // digging through dialerConn to extract the *net.TCPConn