docs: @Override
      public StringBuffer getRequestURL() {
  
          if (m_requestUrl != null) {
              return m_requestUrl;
          }
          StringBuffer buf = new StringBuffer(128);
          buf.append(getScheme());
          buf.append("://");
          buf.append(getServerName());
          buf.append(":");
          buf.append(getServerPort());
          buf.append(getRequestURI());
          m_requestUrl = buf;
          return m_requestUrl;
      }