Fix lockup if sender is used to send and empty buffer
Work around XNIO-199
HttpSession.removeAttribute(...) should not trigger attribute removed event if attribute did not exist.
HttpSession.setAttribute(name, null) should trigger valueUnbound binding event.
HttpSession.setAttribute(name, value) should not trigger any events if value == old value.
[UNDERTOW-36] Remote the getName() method from the AuthenticationMechanism interface as mechanisms now pass in the name using the notification API instead.
Implement getRequestedSessionId()
Add channel facade so still running requests can't modify the underlying channel
If the exchange is ended by the authenticate call don't continue processing