HttPRequest重寫，解決資源戰勝/鏈接超時/分塊下載事件通知 問題。

/************************************************************************************** 文 件 名：WebRequest.cs* 創建時間：2015-06-18* 作 者：Sam Shum (s.sams＠msn.com)* 說 明：解決WebHttpRequest下載網頁數據出現問題 * 修改時間：2015-06-19* 修 改 人：Sam Shum*************************************************************************************/using System;using System.Collections.Generic;using System.ComponentModel;using System.IO;using System.IO.Compression;using System.Linq;using System.Net;using System.Text;using System.Web;namespace S.Sams.Common{    public class HttpRequest    {        public HttpRequest()        {            //string Url = "http://localhost:5192/api/Cab/5";            //string httpMethod = "PUT";            //string httpContent = "{'Name': 'B90', 'Color': 'Green', 'Height': 1590, 'Width': 4500 }";            //Encoding httpCode = Encoding.Default;            //Console.WriteLine(Get(Url, httpMethod, httpContent, httpCode));            setEncoding = Encoding.Default;        }        public HttpRequest(string url, string method) : base()        {            setUrl = url;            setMethod = method;        }        /// <summary>        /// 服務請求地址 http://www.aaa.com/        /// </summary>        public string setUrl { get; set; }        /// <summary>        /// 服務請求方法：GET/POST/PUT/DELETE        /// </summary>        public string setMethod { get; set; }        /// <summary>        /// 設置服務請求數據類型        /// </summary>        [DefaultValue("text/html")]        public string setContentType { get; set; }        /// <summary>        /// 設置服務頁面編碼        /// </summary>        public Encoding setEncoding { get; set; }        public delegate void DownloadStartDelegate(int httpStatusCode);        public delegate void DownloadProcessDelegate(long totalLength, long DownloadedByte, float percent);        public delegate void DownloadEndDelegate(long totalLength);        public event DownloadStartDelegate DownloadStart;        public event DownloadProcessDelegate DownloadProcess;        public event DownloadEndDelegate DownloadEnd;        public string Get()        {            return Get(setUrl);        }        public string Get(string setUrl)        {            return Get(setUrl, "GET", null, setEncoding);        }        public string Get(string setUrl, string httpContent)        {            return Get(setUrl, "POSE", httpContent, setEncoding);        }        public string Get(string Url, string httpMethod, string httpContent, Encoding httpCode)        {            if (string.IsNullOrWhiteSpace(Url) || string.IsNullOrWhiteSpace(httpMethod))            {                throw new ArgumentException("Url or HttpMethod 參數不能為空！");            }            GC.Collect();            StringBuilder content = new StringBuilder();            HttpWebRequest request = null;            HttpWebResponse response = null;            StreamWriter sw = null;            try            {                ServicePointManager.DefaultConnectionLimit = 512;                request = WebRequest.Create(Url) as HttpWebRequest;                request.Method = httpMethod;                request.AllowAutoRedirect = true;                request.KeepAlive = false;                request.Accept = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; Maxthon 2.0)";                request.ContentType = setContentType; //"application/octet-stream";                request.Proxy = null;                if (httpContent != null && !string.IsNullOrWhiteSpace(httpContent))                {                    using (sw = new StreamWriter(request.GetRequestStream()))                    {                        sw.Write(httpContent);                    }                }                using (response = request.GetResponse() as HttpWebResponse)                {                    if (this.DownloadStart != null)                        this.DownloadStart((int)response.StatusCode);                    Stream stream = response.GetResponseStream();                    if (response.ContentEncoding.ToLower().Contains("gz