code: func writeMethodSelection(conn net.Conn) error {
  	message := []byte{socks5Version, socks5AuthNotRequired}
  
  	n, err := conn.Write(message)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	if n != len(message) {
  		return trace.BadParameter("wrote: %v wanted to write: %v", n, len(message))
  	}
  
  	return nil
  }
docs: // writeMethodSelection writes out the response to the authentication methods.
  // Right now, only SOCKS5 and "no authentication methods" is supported.