docs: protected String normalizeUrl(String url) {
      try {
        URL requestURL = new URL(url);
        StringBuilder normalized = new StringBuilder(requestURL.getProtocol().toLowerCase()).append("://").append(requestURL.getHost().toLowerCase());
        if ((requestURL.getPort() >= 0) && (requestURL.getPort() != requestURL.getDefaultPort())) {
          normalized.append(":").append(requestURL.getPort());
        }
        normalized.append(requestURL.getPath());
        return normalized.toString();
      }
      catch (MalformedURLException e) {
        throw new IllegalStateException("Illegal URL for calculating the OAuth signature.", e);
      }
    }