protected override string SendPost(string url, string postData, string referer, bool allowRedirect)
        {
            var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
            httpWebRequest.AllowAutoRedirect = allowRedirect;
            httpWebRequest.Method = "POST";
            httpWebRequest.UserAgent = UserAgent;
            httpWebRequest.ContentType = "application/x-www-form-urlencoded";
            if (!string.IsNullOrEmpty(Proxy))
            {
                httpWebRequest.Proxy = new WebProxy(Proxy);
            }
            if (!string.IsNullOrEmpty(Cookies))
            {
                httpWebRequest.Headers.Add(HttpRequestHeader.Cookie, Cookies);
            }
            if (!string.IsNullOrEmpty(referer))
            {
                httpWebRequest.Referer = referer;
            }
            var buffer = Encoding.ASCII.GetBytes(postData);
            httpWebRequest.ContentLength = buffer.Length;
            using (var writer = httpWebRequest.GetRequestStream())
            {
                writer.Write(buffer, 0, buffer.Length);
            }
            using (var httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse())
            {
                Cookies = string.IsNullOrEmpty(httpWebResponse.Headers["Set-Cookie"]) ? "" : httpWebResponse.Headers["Set-Cookie"];
                using (var stream = httpWebResponse.GetResponseStream())
                {
                    using (var reader = new StreamReader(stream, Encoding.GetEncoding(1251)))
                    {
                        return reader.ReadToEnd();
                    }
                }
            }
        }