code: func (s *Server) AppendCertEmbed(certData, keyData []byte) error {
  	if len(certData) == 0 && len(keyData) == 0 {
  		return errNoCertOrKeyProvided
  	}
  
  	cert, err := tls.X509KeyPair(certData, keyData)
  	if err != nil {
  		return fmt.Errorf("cannot load TLS key pair from the provided certData(%d) and keyData(%d): %s",
  			len(certData), len(keyData), err)
  	}
  
  	s.configTLS()
  
  	s.tlsConfig.Certificates = append(s.tlsConfig.Certificates, cert)
  	return nil
  }
docs: // AppendCertEmbed does the same as AppendCert but using in-memory data.