次のコードを .NET 3.5 で実行しようとするとハングします (プロジェクトを .NET 4 に設定すると動作します)
(2分くらい待った - フリーズしそう)
        HttpWebRequest l_oRequest;
        HttpWebResponse l_oResponse;
        if (m_bLoggedIn)
            return true;
        m_oSession = new SSessionIdentifier();
        m_oSession.Cookies = new CookieContainer();
        string l_sHost = "https://website.com";
        // Start the login sequence
        l_oRequest = GetNewRequest(l_sHost, "Login.aspx", m_oSession.Cookies);
        l_oRequest.Timeout = 5000;
        l_oRequest.ReadWriteTimeout = 5000;
        l_oRequest.Method = "POST";
        l_oRequest.Referer = "https://website.com";
        // Set form parameters
        string l_sFormParameters = "user=" + m_sUsername;
        // Convert them to the HTTP stream
        byte[] l_oRequestBuffer = UTF8Encoding.ASCII.GetBytes(l_sFormParameters);
        var l_oRequestStream = l_oRequest.GetRequestStream();
        l_oRequestStream.Write(l_oRequestBuffer, 0, l_oRequestBuffer.Length);
        // I'm setting this to false because otherwise i can't get the cookies i want. And I love them cookies!
        l_oRequest.AllowAutoRedirect = false;
        // Now start the redirection sequence until we get to what we want
        int l_iDTPos = -1;
        // This line hangs
        l_oResponse = (HttpWebResponse)l_oRequest.GetResponse();
        while (l_oResponse.StatusCode == HttpStatusCode.Found)
        {
                // Yada Yada
これは GetNewRequest 関数です。
    private HttpWebRequest GetNewRequest(string host, string targetUrl, CookieContainer a_oCookieJar)
    {
        HttpWebRequest l_oRequest = (HttpWebRequest)HttpWebRequest.Create(host + targetUrl);
        l_oRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0.2) Gecko/20100101 Firefox/10.0.2";
        l_oRequest.ContentType = "application/x-www-form-urlencoded";
        l_oRequest.AllowAutoRedirect = false;
        l_oRequest.CookieContainer = a_oCookieJar;
        return l_oRequest;
    }
ドキュメントで 3.5 と 4 の間の変更を見つけることができませんでした。誰かがそのような問題に遭遇しましたか?