响应来自HttpWebRequest的内容编码问题

 var pageurl = new Uri(url, UriKind.Absolute);

        var request = (HttpWebRequest)WebRequest.Create(pageurl);
        request.Method = \"GET\";
        request.AutomaticDecompression = DecompressionMethods.GZip;
        request.KeepAlive = false;
        request.ConnectionGroupName = Guid.NewGuid().ToString();
        request.ServicePoint.Expect100Continue = false;
        request.Pipelined = false;
        request.MaximumResponseHeadersLength = 4;

        if (ignoreCertificateErrors)
        {
            ServicePointManager.ServerCertificateValidationCallback += AcceptAllCertificatePolicy;
        }

        var response = (HttpWebResponse)request.GetResponse();


    if (response != null)
        {
            using (var reader = new StreamReader(response.GetResponseStream()))
            {
                return reader.ReadToEnd();
            }
        }