public class HttpClient
    {
        private const int BufSize = 0xffff;
        private static MemoryStream Download(string url)
        {
            var request = (HttpWebRequest)WebRequest.Create(url);
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                using (var rs = response.GetResponseStream())
                {
                    var ms = new MemoryStream();
                    rs.CopyTo(ms, BufSize);
                    ms.Position = 0;
                    return ms;
                }
            }
        }

        private static TextReader DownloadText(string url)
        {
            return new StreamReader(Download(url));
        }

        public static string DownloadString(string url)
        {
            using (var tr = DownloadText(url))
            {
                return tr.ReadToEnd();
            }
        }
    }