One-shot semantics in GHC event manager

[Kazu Yamamoto (=?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?=)]

Ben,

> Hmm, uh oh.  Thanks for testing this. I'll try to reproduce this on my
> end. It looks like it shouldn't be so hard as even the single-threaded
> performance regresses drastically. Just to confirm, you are using the
> latest revision of D347?

I used the following as you suggested:

	https://github.com/bgamari/packages-base/compare/ghc:ghc-7.8...event-rework

I cannot tell whether or not this is idential to D347.

--Kazu