This feature can be enabled by setting the [Config.EncryptedClientHelloConfigList]

	}
	if *verifyPeer {
		cfg.ClientAuth = VerifyClientCertIfGiven
	}

	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 {

	SymmetricCipherSuite []echCipher

	MaxNameLength uint8
	PublicName    []byte
	Extensions    []echExtension
}

var errMalformedECHConfig = errors.New("tls: malformed ECHConfigList")

// parseECHConfigList parses a draft-ietf-tls-esni-18 ECHConfigList, returning a
// slice of parsed ECHConfigs, in the same order they were parsed, or an error
// if the list is malformed.
func parseECHConfigList(data []byte) ([]echConfig, error) {

	// Use of KeyLogWriter compromises security and should only be
	// used for debugging.
	KeyLogWriter io.Writer

	// EncryptedClientHelloConfigList is a serialized ECHConfigList. If
	// provided, clients will attempt to connect to servers using Encrypted
	// Client Hello (ECH) using one of the provided ECHConfigs. Servers
	// currently ignore this field.
	//