.NET HttpClient - 远程主机强制关闭现有连接

我从 ASP.NET MVC 控制器调用了以下代码：

protected string PostData(string url, ByteArrayContent content)
        {
            using (var client = new HttpClient())
            {
                client.Timeout = TimeSpan.FromDays(1);
                return client.PostAsync(url, content).Result.Content.ReadAsStringAsync().Result;
            }
        }

如果我将数据发布到需要一些时间执行的 REST 服务，我会收到以下错误：

System.AggregateException: One or more errors occurred. ---> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
   at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
   --- End of inner exception stack trace ---
   at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
   at System.Net.PooledStream.EndRead(IAsyncResult asyncResult)
   at System.Net.Connection.ReadCallback(IAsyncResult asyncResult)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
   at System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at System.Threading.Tasks.Task`1.get_Result()
   at Libcor.Services.Ssp.External.ExternalServiceBase.PostData(String absoluteUrl, ByteArrayContent content)

REST 服务仍然在后台完成其工作，但 ASP.NET MVC 会出现此异常。对于运行时间较短的服务效果很好。我该如何防止这种情况发生？

添加这个有帮助：

_client.DefaultRequestHeaders.Add("Connection", "Keep-Alive");
_client.DefaultRequestHeaders.Add("Keep-Alive", "3600");

我设法使请求保持足够长的活动时间，以便它能够正常完成并收到有效的响应。