StreamWriter未正确关闭？(StreamWriter not closing correctly?)

 我正确地使用StreamWriter类时遇到了一些麻烦。 我需要发布大约10个对象，但最多只有一对。 但是，在2个帖子之后，第三个帖子没有通过并且超时。 我意识到这是因为你可以拥有的最大连接数为2.但是，我很困惑为什么我在2之后被停止，因为我（想）我正在关闭我的StreamWriter连接。 这是我的代码： 
 
var httpWebRequest = (HttpWebRequest)WebRequest.Create("my url"); 
httpWebRequest.ContentType = "text/json";
httpWebRequest.Method = "POST";
//var data = json data

using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
    streamWriter.Write(data);
    streamWriter.Close();
}
 
 我认为using语句会自动关闭它，但它没有，所以我添加了Close（）行。 但是，这似乎没有做任何事情。 调试器在第三次尝试时卡在使用线上。 如果我将servicePointPoint.DefaultConnectionLimit设置为类似于10的东西，那么一切正常，但我很困惑为什么我写的没有。 任何帮助，将不胜感激！ 

I'm having some trouble using the StreamWriter class correctly. I have about 10 objects I need to post, but only a couple at a time at most. However, after 2 posts, the third does not go through and times out. I realize this is because the max connections you can have is 2. However, I'm confused as to why I am being stopped after 2 since I (think) I am closing my StreamWriter connection. Here is my code:
 
var httpWebRequest = (HttpWebRequest)WebRequest.Create("my url"); 
httpWebRequest.ContentType = "text/json";
httpWebRequest.Method = "POST";
//var data = json data

using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
    streamWriter.Write(data);
    streamWriter.Close();
}
 
I thought the using statement would close it automatically, but it didn't, so I added the Close() line. However, this didn't seem to do anything. The debugger gets stuck on the using line on the third try. If I setServicePointManager.DefaultConnectionLimit to something like 10, everything works, but I'm confused why what I have written doesn't. Any help would be appreciated!

原文：