详细解读ASP.NET的异步

static void Main()  
{  
    var url = new Uri("http://localhost:8012/Handler.ashx");  
    var num = 50;  
    for (int i = 0; i < num; i++)  
    {  
        var request = WebRequest.Create(url);  
        request.GetResponseAsync().ContinueWith(t =>  
        {  
            var stream = t.Result.GetResponseStream();  
            using (TextReader tr = new StreamReader(stream))  
            {  
                Console.WriteLine(tr.ReadToEnd());  
            }  
        });  
    }  
    Console.ReadLine();  
} 

这里，我们同时发起了50个请求，然后观察响应的情况。

【注意】后面的结果会因为操作系统、IIS版本、管道模式、.NET版本、配置项 的不同而不同，以下结果为在Windows Server 2008 R2 + IIS7.5 + .NET 4.5 beta(.NET 4 runtime) + 默认配置 中测试的结果，在没有特别说明的情况下，均为重启IIS后第一次运行的情况。
这个程序在我的电脑运行结果是这样的： 

TId:6   App:35898671    Begin:55:30,3176        End:55:40,3182  TPool:2  
TId:5   App:22288629    Begin:55:30,3176        End:55:40,3212  TPool:2  
TId:7   App:12549444    Begin:55:31,0426        End:55:41,0432  TPool:3  
TId:8   App:22008501    Begin:55:31,5747        End:55:41,5752  TPool:4  
TId:9   App:37121646    Begin:55:32,1067        End:55:42,1073  TPool:5  
TId:10  App:33156464    Begin:55:32,6387        End:55:42,6393  TPool:6  
TId:11  App:7995840     Begin:55:33,1707        End:55:43,1713  TPool:7  
TId:12  App:36610825    Begin:55:33,7028        End:55:43,7033  TPool:8  
TId:13  App:20554616    Begin:55:34,2048        End:55:44,2054  TPool:9  
TId:14  App:15510466    Begin:55:35,2069        End:55:45,2074  TPool:10  
TId:15  App:23324256    Begin:55:36,2049        End:55:46,2055  TPool:11  
TId:16  App:34250480    Begin:55:37,2050        End:55:47,2055  TPool:12  
TId:17  App:58408916    Begin:55:38,2050        End:55:48,2056  TPool:13  
TId:18  App:2348279     Begin:55:39,2051        End:55:49,2057  TPool:14  
TId:19  App:61669314    Begin:55:40,2051        End:55:50,2057  TPool:15  
TId:6   App:35898671    Begin:55:40,3212        End:55:50,3217  TPool:15  
TId:5   App:22288629    Begin:55:40,3232        End:55:50,3237  TPool:15  
TId:7   App:12549444    Begin:55:41,0432        End:55:51,0438  TPool:15  
TId:8   App:22008501    Begin:55:41,5752        End:55:51,5758  TPool:15  
TId:9   App:37121646    Begin:55:42,1073        End:55:52,1078  TPool:15  
TId:10  App:33156464    Begin:55:42,6393        End:55:52,6399  TPool:15  
TId:11  App:7995840     Begin:55:43,1713        End:55:53,1719  TPool:15  
TId:12  App:36610825    Begin:55:43,7043        End:55:53,7049  TPool:15  
TId:13  App:20554616    Begin:55:44,2054        End:55:54,2059  TPool:15  
TId:20  App:36865354    Begin:55:45,2074        End:55:55,2080  TPool:16  
TId:14  App:15510466    Begin:55:45,2084        End:55:55,2090  TPool:16  
TId:21  App:3196068     Begin:55:46,2055        End:55:56,2061  TPool:17  
TId:15  App:23324256    Begin:55:46,2065        End:55:56,2071  TPool:17  
TId:22  App:4186222     Begin:55:47,2055        End:55:57,2061  TPool:18  
TId:16  App:34250480    Begin:55:47,2065        End:55:57,2071  TPool:18  
TId:23  App:764807      Begin:55:48,2046        End:55:58,2052  TPool:19  
TId:17  App:58408916    Begin:55:48,2056        End:55:58,2062  TPool:19  
TId:24  App:10479095    Begin:55:49,2047        End:55:59,2052  TPool:20  
TId:18  App:2348279     Begin:55:49,2057        End:55:59,2062  TPool:20  
TId:25  App:4684807     Begin:55:50,2047        End:56:00,2053  TPool:21  
TId:19  App:61669314    Begin:55:50,2057        End:56:00,2063  TPool:21  
TId:6   App:35898671    Begin:55:50,3227        End:56:00,3233  TPool:21  
TId:5   App:22288629    Begin:55:50,3237        End:56:00,3243  TPool:21  
TId:7   App:12549444    Begin:55:51,0438        End:56:01,0443  TPool:21  
TId:8   App:22008501    Begin:55:51,5758        End:56:01,5764  TPool:21  
TId:9   App:37121646    Begin:55:52,1078        End:56:02,1084  TPool:21  
TId:10  App:33156464    Begin:55:52,6399        End:56:02,6404  TPool:21  
TId:11  App:7995840     Begin:55:53,1719        End:56:03,1725  TPool:21  
TId:26  App:41662089    Begin:55:53,7049        End:56:03,7055  TPool:22  
TId:12  App:36610825    Begin:55:53,7059        End:56:03,7065  TPool:22  
TId:13  App:20554616    Begin:55:54,2069        End:56:04,2075  TPool:22  
TId:27  App:46338128    Begin:55:55,2070        End:56:05,2076  TPool:23  
TId:14  App:15510466    Begin:55:55,2090        End:56:05,2096  TPool:23  
TId:20  App:36865354    Begin:55:55,2090        End:56:05,2096  TPool:23  
TId:28  App:28975576    Begin:55:56,2051        End:56:06,2056  TPool:24 

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