code: @Nonnull
    @Nonempty
    public String getRequestValue ()
    {
      final String sCombined = StringHelper.getConcatenatedOnDemand (m_sUserName,
                                                                     HttpBasicAuth.USERNAME_PASSWORD_SEPARATOR,
                                                                     m_sPassword);
      return HttpBasicAuth.HEADER_VALUE_PREFIX_BASIC + " " + Base64.safeEncode (sCombined, HttpBasicAuth.CHARSET);
    }
docs: Create the request HTTP header value for use with the
  {@link com.helger.commons.http.CHttpHeader#AUTHORIZATION} header name.
  
  @return The HTTP header value to use. Neither <code>null</code> nor empty.