public async Task <IActionResult> PostAsync([FromBody] AddUserReq req, CancellationToken cancellationToken)
        {
            var(code, msg) = req.Valid();

            if (code != ApiReturnCode.Succeed)
            {
                return(BadRequest(ApiSlimResponse.GetResult(code, msg)));
            }

            var res = await _svc.AddUserAsync(req.BuildAddUserInput(TraceId, UserIp), cancellationToken);

            return(Ok(res));
        }