aio_write and PRUS_MORETOCOME

[John Baldwin]

For folks who are interested, I have uploaded a patch to phabricator that
will set PRUS_MORETOCOME when there are multiple writes queued up to a
socket via aio_write().  This mostly matters for TCP.  Silly arc wouldn't
let me add 'network' to the review, but you can find the revision at

https://reviews.freebsd.org/D8955

if you'd like to comment/review.

-- 
John Baldwin