c#写的从http路径下载文件速度很慢，怎么改进呢？
WebRequest方式下载，速度只有30KB/s
[解决办法]
看看是不是这个原因:

What I have found to be the main culprit with slow web requests is the proxy property. If you set this property to null before you call the GetResponse method the query will skip the proxy autodetect step.

The proxy autodetect was taking up to 7 seconds to query before returning the response. It is a little annoying that this property is set on by default for the HttpWebRequest object.

来自:
http://stackoverflow.com/questions/2519655/httpwebrequest-is-extremely-slow