MLton.Socket.shutdown{Read,Write}

[Stephen Weeks]

> The problem is one of surprise.  Unix shutdown doesn't close, so I wouldn't
> expect MLton's to do so, and I can get pimped if it does.  It isn't a big
> deal, but that is enough to decide the case in my mind.

How can you get pimped?  Remember, closing twice is OK.  If it doesn't close,
then I think everyone's gonna end up writing

flushOut out
shutdownWrite out
close out

In fact, I am a bit worried because if you don't do the flush before the
shutdown, then the close is going to try to flush and get an exception.