docs: public static String getRemoteAddr(final HttpServletRequest request) {
          String ret = request.getHeader("X-forwarded-for");
          if (StringUtils.isBlank(ret)) {
              ret = request.getHeader("X-Real-IP");
          }
          if (StringUtils.isBlank(ret)) {
              return request.getRemoteAddr();
          }
  
          return ret.split(",")[0];
      }