docs: func cookieURLScheme(u string) (string, error) {
  	parts := strings.SplitN(u, "://", 2)
  	if len(parts) != 2 {
  		return "", fmt.Errorf("invalid cookie URL, missing scheme")
  	}
  
  	scheme := strings.ToLower(parts[0])
  	if scheme != "http" && scheme != "https" && scheme != "http*" {
  		return "", fmt.Errorf("invalid cookie URL scheme. Expect http, https, or http*. Go, %s", scheme)
  	}
  
  	return scheme, nil
  }