class Program
    {
        static Func<string, bool, CookieContainer, string> func;
        static void Main(string[] args)
        {
            func = Get;
            func.BeginInvoke("http://www.sql.ru/forum/1103286/async-await-i-task-t-na-primere-zagruzki-strani", true, new CookieContainer(), MyWorker, null);
            Console.Read();
        }

        static void MyWorker(IAsyncResult result)
        {
           var str= func.EndInvoke(result);
            Console.WriteLine(str);
        }

        public static string Get(string url, bool clearCookie,  CookieContainer container)
        {
            string output = null;
            try
            {
                HttpWebRequest WebReq = (HttpWebRequest)WebRequest.Create(url);
                if (clearCookie) WebReq.CookieContainer = new CookieContainer();
                else WebReq.CookieContainer = container;
                WebReq.Method = "GET";
                WebReq.AllowAutoRedirect = true;
                WebReq.ContentType = "application/x-www-form-urlencoded";

                HttpWebResponse WebResp = (HttpWebResponse)WebReq.GetResponse();
                Stream Answer = WebResp.GetResponseStream();
                container = WebReq.CookieContainer;
                StreamReader _Answer = new StreamReader(Answer, Encoding.GetEncoding(1251));
                output = _Answer.ReadToEnd();
                return output.Trim() + "\n";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }
    }