public static byte[] Get(string url, Action<int> onPercentChange = null) {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            request.Timeout = kRequestTimeout;
            request.Method = "GET";
            request.Referer = url;
            request.CookieContainer = _cookie;

            return Download(request, onPercentChange);
        }

        private static byte[] Download(HttpWebRequest request, Action<int> onPercentChange) {

            
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            long length = response.ContentLength;
            int bytePerTime = (int)(length / 100 + 1);

            byte[] receiveBytes = new byte[bytePerTime * 100];

            BinaryReader br = new BinaryReader(response.GetResponseStream());

            

            for (int k = 0; k < 100; k++) {
                byte[] buffer = br.ReadBytes(bytePerTime);
                Array.Copy(buffer, 0, receiveBytes, bytePerTime * k, buffer.Length);
                if (onPercentChange != null)
                    onPercentChange(k);
            }

            br.Close();
            response.Close();

            return receiveBytes;
        }