c# HttpClient上傳和下載的進度顯示問題

WebClient中有DownloadProgressChangedEventHandler等事件可以響應http請求(或者其他web請求)的進度。
在c# 5.0中,HttpClient的函數都是以Task異步函數存在，沒有事件可以回調顯示上傳或下載的進度。
我找了很久，終於發現ProgressMessageHandler 可以解決這個問題，
具體示例代碼
               HttpClientHandler hand = new HttpClientHandler();
                ProgressMessageHandler processMessageHander = new ProgressMessageHandler(hand);
                HttpClient localHttpClient = new HttpClient(processMessageHander);

                HttpRequestMessage httpRequestMessage = new HttpRequestMessage();

                httpRequestMessage.Method = HttpMethod.Put;
                httpRequestMessage.Content = new StreamContent(content);

                //for upload

                processMessageHander.HttpSendProgress += (sender, e) =>
                {
                    int num = e.ProgressPercentage;     //you can use HttpProgressEventArgs e

                };

                //for download

               // processMessageHander.HttpReceiveProgress += (sender, e) =>
              //   {
               //      int num = e.ProgressPercentage;

              //   };

                HttpResponseMessage test = await localHttpClient.SendAsync(httpRequestMessage);

                // dispose the resource