VB.NET导入随机代理WebRequest

Question

您能帮我实现一个随机更改的代理系统吗？ 我不知道该把手放在哪里！

Private Function Auth(user As String, password As String) As String
        Dim ret = String.Empty
        Try
            Dim data = "Nothing for now"
            Dim byteArray As Byte() = Encoding.UTF8.GetBytes(data)
            Dim webReq = DirectCast(WebRequest.Create(New Uri("Website")), HttpWebRequest)
            webReq.Method = "POST"
            webReq.ContentType = "application/json"
            webReq.ContentLength = byteArray.Length
            Dim newStream As Stream = webReq.GetRequestStream()
            newStream.Write(byteArray, 0, byteArray.Length)
            newStream.Close()
            Dim response = DirectCast(webReq.GetResponse(), HttpWebResponse)
            Dim sr = New StreamReader(response.GetResponseStream(), Encoding.[Default])
            ret = sr.ReadToEnd()
            sr.Close()
            response.Close()
            newStream.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        Return ret
    End Function