public static List<int> GetHttp (string httpUrl)
        {
            List<int> result = new List<int>(); 
            HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create (httpUrl);
            myReq.Method = "GET";
            try
            {                
                HttpWebResponse HttpWResp = (HttpWebResponse)myReq.GetResponse ();
                System.IO.Stream myStream = HttpWResp.GetResponseStream ();
                int data = -1;
                while ((data = myStream.ReadByte()) != -1)
                {
                    // 因为不清楚 myStream.Length 是否真实字节流长度. 所以用了动态数组List
                    result.Add(data);
                }
            }
            catch (Exception exp)
            {
                Debug.Log(exp.ToString());
            }
            return result ; 
        }