Kestrel takes 2-3 seconds to shutdown if any connections have been made

[AspNetSmurfLab]

Kestrel is taking 2-3 seconds to shutdown (e.g. after Ctrl-C) if any connections have been made to it. This is causing the development experience in Visual Studio to be poor due to the long time it takes to get the server going again after making a code change.

Repro steps

1. Start the server
2. Immediately Ctrl-C to end it without making a request
3. It exits immediately
4. Start the server again
5. Make a request from a browser then close the browser
6. Ctrl-C the kestrel server
7. It takes 2-3 seconds for the process to end

by @DamianEdwards

[muratg]

OK, let's investigate what we can do for Beta 8.

[halter73]

@muratg I tested the shalter/247 branch referenced above with the new WTE build. This seemed to reduce the time window where you could get a 502.3 response, but didn't eliminate it completely.

Bill thinks that the change to kill iisexpress on ctrl+f5 could fix the 502.3 issue as well, so I'm waiting on that change before doing any further work on this.

[muratg]

@halter73 Sounds good. If WTE change ends up eliminating the need to do this in Beta 8, please move to RC1.