/// <summary>
        /// 请求url
        /// </summary>
        /// <param name="client"></param>
        /// <param name="url"></param>
        /// <param name="httpMethod"></param>
        /// <returns></returns>
        private static string DoRequest(IDiscoveryClient client, string url, HttpMethod httpMethod)
        {
            string result = "";

            try
            {
                Uri            uri     = client.LookupService(new Uri(url));
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
                request.Method = httpMethod.Method;

                try
                {
                    using (Stream stream = ((HttpWebResponse)request.GetResponse()).GetResponseStream())
                    {
                        result = new StreamReader(stream, Encoding.UTF8).ReadToEnd();
                    }
                }
                catch (WebException exception1)
                {
                    using (Stream stream2 = ((HttpWebResponse)exception1.Response).GetResponseStream())
                    {
                        result = new StreamReader(stream2).ReadToEnd();
                    }
                }
            }
            catch (Exception exception)
            {
                result = exception.Message;
            }
            return(result);
        }