Stop using "Int" for microsecond delays in "base"

[Evan Laforge]

On Wed, Mar 30, 2011 at 12:15 PM, Edward Kmett <ekmett at gmail.com> wrote:
> Of course, in this particular case, worrying about the overhead of
> manipulating an Integer when you are in the process of jumping through the
> hoops to put your thread to sleep is somewhat silly. ;)

Yes, but that's only because the conversation has gotten off track.  I
was answering the question "are Ints good for anything beyond the
FFI?" which was raised as a result of the thread delay thing.  Sorry
about that.

Integer sounds reasonable enough for threadDelay.