code: func getXForwardedTLSClientCert(logger logrus.FieldLogger, certs []*x509.Certificate) string {
  	var headerValues []string
  
  	for _, peerCert := range certs {
  		headerValues = append(headerValues, extractCertificate(logger, peerCert))
  	}
  
  	return strings.Join(headerValues, ",")
  }
docs: // getXForwardedTLSClientCert Build a string with the client certificates.