docs: public static <T> String generateSign(RestRequestParam<T> param, String secretkey) {
      TreeMap<String, String> paramsMap = new TreeMap<String, String>();
      paramsMap.put("accesskey", param.getCommon().getAccesskey());
      paramsMap.put("timestamp", Long.toString(param.getCommon().getTimestamp()));
  
      //    for (Map.Entry<String, String> entry : param.getData())
      //    {
      //        paramsMap.put(entry.getKey(), entry.getValue().toString());
      //    }
      paramsMap.put("secretkey", secretkey);
      return generateSignByRule(paramsMap);
    }