public async Task<string> SendDataAsync(HttpMethod httpMethod, string requestUrl, HttpContent postContent = null, string cookies = "")

         {

             HttpClientHandler httpHandler = new HttpClientHandler()

             {

                 AllowAutoRedirect = true,

                 //CookieContainer = new CookieContainer(),

                 UseCookies = false,

                 AutomaticDecompression = DecompressionMethods.GZip

             };

             using (HttpClient httpClient = new HttpClient(httpHandler))

             {

                 httpClient.DefaultRequestHeaders.ExpectContinue = false;

                 httpClient.DefaultRequestHeaders.Add("Accept", "*/*");

                 httpClient.DefaultRequestHeaders.Add("Accept-Encoding", "gzip, deflate");

                 httpClient.DefaultRequestHeaders.Add("Accept-Language", " zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3");

                 httpClient.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0");

                 //var response = await httpClient.GetAsync(sUrl);

                 //return (await response.Content.ReadAsAsync<AvResult>());

                 string sResult;

                 try

                 {

                     HttpRequestMessage request = new HttpRequestMessage(httpMethod, requestUrl);

                     bool isNullCookie = string.IsNullOrEmpty(cookies);

                     if (!isNullCookie)

                     {

                         //httpHandler.CookieContainer.SetCookies(new Uri(requestUrl), cookies);

                         request.Headers.Add("Cookie", cookies);

                     }

                     if (httpMethod.Method == "POST")

                         request.Content = postContent;

                     var response = await httpClient.SendAsync(request);

                     sResult = await response.Content.ReadAsStringAsync();

                 }

                 catch (Exception ex)

                 {

                     sResult = ex.Message;

                 }

                 return sResult;

             }

         }