docs: public static String get(FullHttpRequest fullHttpRequest) {
          HttpHeaders httpHeaders = fullHttpRequest.headers();
          if (isNodeLegal(httpHeaders) && !StringUtil.isEmpty(httpHeaders.get(Constant.XIAN_MSG_ID_HEADER))) {
              return httpHeaders.get(Constant.XIAN_MSG_ID_HEADER);
          }
          return null;
      }