async-Task

public async Task<ActionResult> DownloadImage(string mediaId)
        {
            string accessToken = string.Empty;
            string file = string.Empty;
            string content = string.Empty;
            string strpath = string.Empty;
            string savepath = string.Empty;
            string stUrl = string.Empty;

            HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(stUrl);

            req.Method = "GET";
            await new Task(() =>
            {
                HttpWebResponse myResponse = (HttpWebResponse)req.GetResponse();

                strpath = myResponse.ResponseUri.ToString();
                WebClient mywebclient = new WebClient();
                savepath = Server.MapPath("~/Upload/UploadImage") + "\\" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + (new Random()).Next().ToString().Substring(0, 4) + ".jpg";
                ///C:inetpub\wwwroot\Upload\UploadImage
                try
                {
                    mywebclient.DownloadFile(strpath, savepath);
                    file = savepath.Substring(18);
                }
                catch (Exception ex)
                {
                    savepath = ex.ToString();
                }
            });

            return Json(new { Link = file }, JsonRequestBehavior.AllowGet);
        }