Stream stream = request.GetResponse().GetResponseStream();

            FileStream file = new FileStream(_filePath, FileMode.Create);

            CopyTo(stream, file, 1024);

            file.Close();


  void CopyTo(Stream source, Stream dest, int buffersize)
        {
            int num;
            byte[] buffer = new byte[buffersize];

            while ((num = source.Read(buffer, 0, buffer.Length)) != 0)
                dest.Write(buffer, 0, num);
        }

 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = WebRequestMethods.Http.Get;
            request.KeepAlive = true;