C#

int c,cc=4096;

public static ManualResetEvent allDone = new ManualResetEvent(false);

FileStream fs = new FileStream( "file to post",.......);


asyncResult = request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), requestState);
allDone.WaitOne();
allDone.Reset();
c = fs.Read(b, 0, cc);
AsyncCallback callback = new AsyncCallback(WriteCallback);
int n = 0;
while (c > 0)
{
    asyncResult = requestState.dataStream.BeginWrite(b, 0, c, callback, requestState);
    requestState.waitHandle = ThreadPool.RegisterWaitForSingleObject(allDone, new WaitOrTimerCallback(TimeoutCallback), requestState, 3000, true);
    allDone.WaitOne();
    allDone.Reset();
    c = fs.Read(b, 0, cc);
}
requestState.dataStream.Close();

//NOTE:if remove the following line, the BeginGetResponse will hang
Thread.Sleep(1000);

asyncResult = request.BeginGetResponse(new AsyncCallback(GetResponseCallback), requestState);
allDone.WaitOne();
allDone.Reset();