WebSocket extensions and permessage-deflate extension

[adam-fowler]

No description provided.

[Joannis]

I assume you've tested this against a third-party implementation as well? If possible, I think we should add a test to verify what happens when there are two different websocket extension at play.

[adam-fowler]

I assume you've tested this against a third-party implementation as well? If possible, I think we should add a test to verify what happens when there are two different websocket extension at play.

The snippet enables permessage-deflate and you can check it against your web browser.
testPerMessageExtensionOrdering checks what happens when you have two extensions in play.