Async Timeout Issue

This class will perform Async HttpWebRequests with a timeout method.

The problem is that everything will be working fine, but after about 10 requests, one of them will timeout, and every single subsequent request will timeout, obviously this isn't working properly...:sick::afrog::eek2:

Can someone help?? This is the 2nd time I've posted this, didn't get a response the first time...

Code:

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Imports System
Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Threading
Imports Microsoft.VisualBasic

Public Class RequestState
    ' This class stores the State of the request.
    Private BUFFER_SIZE As Integer = 1024
    Public requestData As StringBuilder
    Public BufferRead() As Byte
    Public request As HttpWebRequest
    Public response As HttpWebResponse
    Public streamResponse As Stream

    Public Sub New()
        BufferRead = New Byte(BUFFER_SIZE) {}
        requestData = New StringBuilder("")
        request = Nothing
        streamResponse = Nothing
    End Sub 'New
End Class 'RequestState


Class HttpWebRequest_BeginGetResponse

    Public Shared allDone As New ManualResetEvent(False)
    Private BUFFER_SIZE As Integer = 1024
    Private DefaultTimeout As Integer = 20000

    ' 2 minutes timeout
    ' Abort the request if the timer fires.
    Private Shared Sub TimeoutCallback(ByVal state As Object, ByVal timedOut As Boolean)
        If timedOut Then
            Dim request As HttpWebRequest = state
            MsgBox("The Request Timed Out!")
            If Not (request Is Nothing) Then
                request.Abort()
            End If
        End If
    End Sub 'TimeoutCallback


    Shared Sub Main(ByVal proxy As String)

        Try
            ' Create a HttpWebrequest object to the desired URL.
            Dim myHttpWebRequest As HttpWebRequest = WebRequest.Create("http://www.msn.com")

            ' Create an instance of the RequestState and assign the previous myHttpWebRequest
            ' object to its request field. 

            Dim myRequestState As New RequestState()
            myRequestState.request = myHttpWebRequest
            If proxy <> ":" Then
                Dim myProxy As New WebProxy(proxy)
                myHttpWebRequest.Proxy = myProxy
            End If
            Dim myResponse As New HttpWebRequest_BeginGetResponse()

            ' Start the asynchronous request.
            Dim result As IAsyncResult = CType(myHttpWebRequest.BeginGetResponse(New AsyncCallback(AddressOf RespCallback), myRequestState), IAsyncResult)

            ' this line implements the timeout, if there is a timeout, the callback fires and the request aborts.
            ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, New WaitOrTimerCallback(AddressOf TimeoutCallback), myHttpWebRequest, myResponse.DefaultTimeout, True)

            ' The response came in the allowed time. The work processing will happen in the
            ' callback function.
            allDone.WaitOne()

            ' Release the HttpWebResponse resource.
            myRequestState.response.Close()

        Catch e As WebException
            MsgBox(e.Status)
            ' Catch e As Exception
            ' MsgBox(e.Message)
            ' MsgBox(e.StackTrace)
            ' MsgBox(e.InnerException)
        End Try

    End Sub 'Main

    Private Shared Sub RespCallback(ByVal asynchronousResult As IAsyncResult)
        Try
            ' State of request is asynchronous.
            Dim myRequestState As RequestState = CType(asynchronousResult.AsyncState, RequestState)
            Dim myHttpWebRequest As HttpWebRequest = myRequestState.request
            myRequestState.response = CType(myHttpWebRequest.EndGetResponse(asynchronousResult), HttpWebResponse)

            ' Read the response into a Stream object.
            Dim responseStream As Stream = myRequestState.response.GetResponseStream()
            myRequestState.streamResponse = responseStream

            ' Begin the Reading of the contents of the HTML page and print it to the console.
            Dim asynchronousInputRead As IAsyncResult = responseStream.BeginRead(myRequestState.BufferRead, 0, 1024, New AsyncCallback(AddressOf ReadCallBack), myRequestState)
            Return
        Catch e As WebException
            Select Case e.Status
                Case WebExceptionStatus.Success
                Case Else
                    MsgBox(e.Message)
            End Select
        End Try
        allDone.Set()
    End Sub 'RespCallback

    Private Shared Sub ReadCallBack(ByVal asyncResult As IAsyncResult)
        Try

            Dim myRequestState As RequestState = CType(asyncResult.AsyncState, RequestState)
            Dim responseStream As Stream = myRequestState.streamResponse
            Dim read As Integer = responseStream.EndRead(asyncResult)
            ' Read the HTML page and then print it to the console.
            If read > 0 Then
                myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read))
                Dim asynchronousResult As IAsyncResult = responseStream.BeginRead(myRequestState.BufferRead, 0, 1024, New AsyncCallback(AddressOf ReadCallBack), myRequestState)
                Return
            Else
                MsgBox(ControlChars.Lf + "The contents of the Html page are : ")
                If myRequestState.requestData.Length > 1 Then
                    Dim stringContent As String
                    stringContent = myRequestState.requestData.ToString()
                    MsgBox(stringContent)
                End If
                MsgBox("Press any key to continue..........")
                Console.ReadLine()

                responseStream.Close()
            End If

        Catch e As WebException
            MsgBox(ControlChars.Lf + "ReadCallBack Exception raised!")
            MsgBox(ControlChars.Lf + "Message:{0}", e.Message)
            MsgBox(ControlChars.Lf + "Status:{0}", e.Status)
        End Try
        allDone.Set()
    End Sub 'ReadCallBack
End Class 'HttpWebRequest_BeginGetResponse

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