The TLS client now supports the Encrypted Client Hello [draft specification](https://www.ietf.org/archive/id/draft-ietf-tls-esni-18.html).
This feature can be enabled by setting the [Config.EncryptedClientHelloConfigList]

		}
		echConfigs, err := parseECHConfigList(c.config.EncryptedClientHelloConfigList)
		if err != nil {
			return nil, nil, nil, err
		}
		echConfig := pickECHConfig(echConfigs)
		if echConfig == nil {
			return nil, nil, nil, errors.New("tls: EncryptedClientHelloConfigList contains no valid configs")
		}
		ech = &echContext{config: echConfig}

	}

	if *echConfigListB64 != "" {
		echConfigList, err := base64.StdEncoding.DecodeString(*echConfigListB64)
		if err != nil {
			log.Fatalf("parse ech-config-list err: %s", err)
		}
		cfg.EncryptedClientHelloConfigList = echConfigList
		cfg.MinVersion = VersionTLS13
	}

	if len(*curves) != 0 {
		for _, curveStr := range *curves {
			id, err := strconv.Atoi(curveStr)
			if err != nil {

	// If the list contains no valid ECH configs, the handshake will fail
	// and return an error.
	//
	// If EncryptedClientHelloConfigList is set, MinVersion, if set, must
	// be VersionTLS13.
	//
	// When EncryptedClientHelloConfigList is set, the handshake will only
	// succeed if ECH is sucessfully negotiated. If the server rejects ECH,
	// an ECHRejectionError error will be returned, which may contain a new

pkg crypto/tls, method (*ECHRejectionError) Error() string #63369
pkg crypto/tls, method (*QUICConn) StoreSession(*SessionState) error #63691
pkg crypto/tls, type Config struct, EncryptedClientHelloConfigList []uint8 #63369
pkg crypto/tls, type Config struct, EncryptedClientHelloRejectionVerify func(ConnectionState) error #63369
pkg crypto/tls, type ConnectionState struct, ECHAccepted bool #63369

		},
	}
	serverConfig.MinVersion = VersionTLS13
	clientConfig.RootCAs = x509.NewCertPool()
	clientConfig.RootCAs.AddCert(cert)
	clientConfig.MinVersion = VersionTLS13
	clientConfig.EncryptedClientHelloConfigList, _ = hex.DecodeString("0041fe0d003d0100200020204bed0a11fc0dde595a9b78d966b0011128eb83f65d3c91c1cc5ac786cd246f000400010001ff0e6578616d706c652e676f6c616e670000")
	clientConfig.ServerName = "example.golang"

			f.Set(reflect.ValueOf([]uint16{1, 2}))
		case "CurvePreferences":
			f.Set(reflect.ValueOf([]CurveID{CurveP256}))
		case "Renegotiation":
			f.Set(reflect.ValueOf(RenegotiateOnceAsClient))
		case "EncryptedClientHelloConfigList":
			f.Set(reflect.ValueOf([]byte{'x'}))
		case "mutex", "autoSessionTicketKeys", "sessionTicketKeys":
			continue // these are unexported fields that are handled separately
		default: