httpClient.PostAsync调用WebApi导致 A task was canceled

[59從山上下來了]

在一个功能函数中，循环调用下列的POST函数（调用后Sleep 300ms，因为测试中发现接口处理一条一般在200ms以内），发现其请求无法成功，response 返回的都是null。

在开启的线程中运行uploadingLoop，uploadingLoop中的for循环里运行POST
测试时，一个线程去跑uploadingLoop还能成功。实际运行环境下，会有七八个线程在跑uploadingLoop，就不行l了。

报错如下：

System.AggregateException: One or more errors occurred. ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task`1.get_Result()
   at Richon.CollectingCore.UploadingService.Post(String requestUri, String content)
---> (Inner Exception #0) System.Threading.Tasks.TaskCanceledException: A task was canceled.<---

One or more errors occurred.
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task`1.get_Result()
   at Richon.CollectingCore.UploadingService.Post(String requestUri, String content)

        private void uploadingLoop()
        {
            while (this._running)
            {
                int count = this._cache.Count;
                if (count > 0)
                {
                    for (int i = 0; i < count; i++)
                    {
                        var dev = this._cache[i];
                        if (dev != null && dev.HasEnergyInfo && dev.HasDevicePropertyInfo)
                        {
                            using (UploadingService service = new UploadingService())
                            {
                                service.Post(ConfigHelper.DeviceAcquire, dev.ToJson());
                            }
                            _cache.Remove(dev);
                            Thread.Sleep(300);
                        }
                    }
                }
            }
        }

public void Post(string requestUri, string content)
        {
            var httpContent = new StringContent(content, Encoding.UTF8, "application/json");

            HttpResponseMessage response = null;
            try
            {
                response = this._httpClient.PostAsync(requestUri, httpContent).Result;
            }
            catch (Exception e)
            {
                TxtLogger.WriteError(e);
                return;
            }
}