получить Cookie

static string GetCookie()
{
    string url="http://site.ru/user/login";
            
    HttpWebRequest tQ=(HttpWebRequest) HttpWebRequest.Create(url);
    tQ.Host="site.ru";
    tQ.Accept="text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    tQ.UserAgent="Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0";
    tQ.ContentType = "application/x-www-form-urlencoded";
    tQ.Referer=url;
    HttpWebResponse tS=(HttpWebResponse) tQ.GetResponse();
            
    string tC = tS.Headers["Set-Cookie"];
 
        Console.WriteLine(tC); // пусто
    tS.Close();
    return tC;  
}

static string GetCookie()
{
    string url = "https://www.cyberforum.ru/";
 
    HttpWebRequest tQ = (HttpWebRequest)HttpWebRequest.Create(url);
    tQ.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    tQ.UserAgent = "Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0";
    tQ.ContentType = "application/x-www-form-urlencoded";
    tQ.Referer = url;
    HttpWebResponse tS = (HttpWebResponse)tQ.GetResponse();
 
    string tC = tS.Headers["Set-Cookie"];
 
    Console.WriteLine(tC);
    tS.Close();
    return tC;
}

foreach (string key in tS.Headers.AllKeys) {
    string value = hr.Headers[key];
    Console.WriteLine(key + ';' + value);
}