Работа с потоками

HttpWebRequest req = (HttpWebRequest)WebRequest.Create( uri );
IAsyncResult asyncResult = req.BeginGetResponse( null, req );
HttpWebRequest request = (HttpWebRequest) asyncResult.AsyncState;
 using ( var response = request.EndGetResponse( asyncResult ) ) {
     using ( var reader = new StreamReader(response.GetResponseStream(), Encoding.ASCII ) ) {
       string html =  reader.ReadToEnd();
     }
}

 public void send()
            {
                HttpWebRequest reQ = (HttpWebRequest)HttpWebRequest.Create("index.php");
                reQ.Method = "POST";
                reQ.Headers.Add("X-Requested-With", "XMLHttpRequest");
                reQ.Host = ".ru";
                reQ.ContentLength = dat.Length;
                reQ.ServicePoint.Expect100Continue = false;
                reQ.KeepAlive = false;
                reQ.AllowAutoRedirect = true;
                reQ.Headers.Add(HttpRequestHeader.CacheControl, "no-cache");
                reQ.Headers.Add(HttpRequestHeader.Cookie, CCookie);
                reQ.Accept = "image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*";
                reQ.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip, deflate");
                reQ.Headers.Add(HttpRequestHeader.AcceptCharset, "windows-1251,utf-8;q=0.7,*;q=0.7");
                reQ.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
                reQ.Headers.Add(HttpRequestHeader.AcceptLanguage, "ru-ru,ru;q=0.8,en-us;q=0.5,en;q=0.3");
                reQ.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; InfoPath.2)";
                reQ.ContentType = "multipart/form-data; boundary=41184676334"; 
                reQ.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), reQ);
               
                
            }
 
            public void GetRequestStreamCallback(IAsyncResult asynchronousResult)
            {
                HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
                Stream postStream = request.EndGetRequestStream(asynchronousResult);
 
                postStream.Write(dat, 0, dat.Length);
                postStream.Close();
                request.BeginGetResponse(new AsyncCallback(GetResponseCallback), request);
            }
          
 
            public void GetResponseCallback(IAsyncResult asynchronousResult)
            {
                HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
                HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
                Stream streamResponse = response.GetResponseStream();
                StreamReader streamRead = new StreamReader(streamResponse);
                string responseString = streamRead.ReadToEnd();
 
 
                streamResponse.Close();
                streamRead.Close();
                response.Close();
 
            }

 System.Threading.Thread thread = null;
        ManualResetEventSlim resEvent = new ManualResetEventSlim(true);
        CancellationTokenSource cts = null;

 void ThreadFunction(object args)
        {
            var input = (System.Tuple<ManualResetEventSlim, CancellationToken>)args;
            input.Item1.Reset();
            System.Net.HttpWebRequest request = System.Net.HttpWebRequest.CreateHttp("http://google.ru");
            IAsyncResult result = request.BeginGetResponse(null, null);
            while (!result.IsCompleted)
            {
                if (input.Item2.IsCancellationRequested)
                {
                    request.Abort();
                    input.Item1.Set();
                    return;
                };
 
            }
            System.Net.WebResponse data = request.EndGetResponse(result);
            //Обработка результата
            //...
            data.Close();
            input.Item1.Set();
        }

 private void Timer(object sender, EventArgs e)
        {
            if (resEvent.IsSet)
            {
                cts = new CancellationTokenSource();
                thread = new Thread(ThreadFunction);
                thread.Start(new Tuple<ManualResetEventSlim, CancellationToken>(resEvent, cts.Token));
            }
        }

  private void button_Click(object sender, EventArgs e)
        {
            if (!resEvent.IsSet)
            {
                cts.Cancel();
                resEvent.Wait();
            }
        }