code: func (s *Server) ListenAndServeTLS(certFile, keyFile string) error {
  	var err error
  	certs := make([]tls.Certificate, 1)
  	certs[0], err = tls.LoadX509KeyPair(certFile, keyFile)
  	if err != nil {
  		return err
  	}
  	// We currently only use the cert-related stuff from tls.Config,
  	// so we don't need to make a full copy.
  	config := &tls.Config{
  		Certificates: certs,
  	}
  	return s.serveImpl(config, nil)
  }
docs: // ListenAndServeTLS listens on the UDP address s.Addr and calls s.Handler to handle HTTP/3 requests on incoming connections.