使用ASP .NET Core，Web API POST / PUT速度很慢

为什么我的web api POST / PUT的响应时间如此慢，代码如下？ POST的json内容只是<= 1024字节 .

方法1和方法2我也试过但结果相同，慢...

已经尝试禁用代理;也慢

// GET API
        var testAsID = Convert.ToInt32(result);  
        var getQueryString = string.Format("CoID={0}&ArID={1}", testCoID, testAsID);  
        var response = await GetWebApiResponse(WebApiMethod.GET, controller, "GetByID", getQueryString);  
        var result = await response.Content.ReadAsStringAsync();

        //  POST
    var newAS = new ASMtnModel()
                {
                    CoID = "LKC3",
                    AsID = 0,
                    ClassID = "AR",
                    AsCode = "AS Test 1",
                    AsNameS = "AS Test 1",
                    AsName1 = "AS Name 1",
                    AsCurr = "RM",
                    AsCat1 = "ZZZZZZ",
                    AsProject = "ZZZZZZZZZZZZZZZ",
                    AsCrTerm = "CASH",
                    AsGLAcID = "",
                    AsGLCcID = "",
                    AsGLScID = "",
                    AsCrLmt = 0,
                    AsCrBal = 0,
                    AsTaxType = "N",
                    AsAccStatus = "1",
                    AsStatus = "A",
                    AsDateOpen = DateTime.Now,
                    AsDateLSal = DateTime.Now,
                    AsDateLPm = DateTime.Now,
                    ApvDate = DateTime.Now,
                    LastUpdateUser = "LLK",
                    LastUpdateDate = DateTime.Now,
                    AsGstDefaultValue = "E"
                };
        var httpResponseMessage = await GetWebApiResponse(WebApiMethod.POST, controller, "Create", "", newAS);  
        var result = await httpResponseMessage.Content.ReadAsStringAsync(); 


        public async Task GetWebApiResponse(WebApiMethod webApiMethod, string controller, string action, string queryString = "", object requestBody = null)
        {
          var request = "/api/" + controller;
          if (!string.IsNullOrEmpty(action))
          {
            request += "/" + action;
          }
          if (!string.IsNullOrEmpty(queryString))
          {
            request += "?" + queryString;
          }

          var httpResponseMessage = new HttpResponseMessage();
          if (webApiMethod == WebApiMethod.GET)
          {
            httpResponseMessage = await _client.GetAsync(request);
          }
          else if (webApiMethod == WebApiMethod.POST)
          {
            string postBody = JsonConvert.SerializeObject(requestBody);
            // Method 1
            //httpResponseMessage = await _client.PostAsync(request, new StringContent(postBody, Encoding.UTF8, "application/json"));

            // Method 2
            using (WebClient wc = new WebClient())
            {
              wc.Proxy = null;
              var hostUrl = _client.BaseAddress.AbsoluteUri;
              if (hostUrl.EndsWith("/"))
              {
                hostUrl = hostUrl.Substring(0, hostUrl.Length - 1);
              }
              var fullApiUrl = hostUrl + request;
              byte[] bytes = System.Text.Encoding.ASCII.GetBytes(postBody);
              wc.Headers[HttpRequestHeader.ContentType] = "application/json";
              var resp = await wc.UploadDataTaskAsync(new Uri(fullApiUrl), bytes);

              httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK);
              httpResponseMessage.Content = new StringContent(System.Text.Encoding.UTF8.GetString(resp));
            }
          }
        }

Fiddler
请求数：1个字节发送：1,604（ Headers ：506;正文：1,098）接收的字节数：121（ Headers ：120;正文：1）

实际表现
ClientConnected：10：07：42.186
ClientBeginRequest：10：11：33.569
GotRequestHeaders：10：11：33.569
ClientDoneRequest：10：11：33.569
确定网关：0ms
DNS查询：0ms
TCP / IP连接：0ms
HTTPS握手：0ms
ServerConnected：10：07：59.041
FiddlerBeginRequest：10：11：33.569 ServerGotRequest：10：11：33.569
ServerBeginResponse：10：12：21.874
GotResponseHeaders：10：12：21.874
ServerDoneResponse：10：12：21.875
ClientBeginResponse：10：12：21.874
ClientDoneResponse：10：12：21.875

Overall Elapsed:    0:00:48.306

响应字节（按内容类型）
〜头〜：120
application / json：1

Server Request Log:

Executed action EB.WebApi.Controllers.ASMtnController.GetAll (EB.WebApi) in 282.741ms

Request starting HTTP/1.1 POST http://localhost:5000/api/ASMtn/Create application/json 1098
dbug: Microsoft.AspNetCore.Routing.Tree.TreeRouter[1]
Request successfully matched the route with name '' and template 'api/ASMtn/Create'.
Request finished in 47928.9705ms 200 application/json; charset=utf-8