* avva: In particular, he pointed out TCP_DEFER_ACCEPT which makes the
  listening socket signal readiness for accept() only after some data
  is actually sent from the other side. It makes sense in cases of
  memcached, but probably won't really matter.

* slab class reassignment still buggy and can crash.  once that's
  stable, server should re-assign pages every 60 seconds or so
  to keep all classes roughly equal.

* calendar queue for early expirations of items, so they don't push
  out other objects with infinite expirations.

* drop root on start, if root. to what? nobody/nogroup? configurable?
