Speed up the worker accept loop
First, reduce no-op fchmod syscalls under heavy traffic.
gettimeofday(2) is a cheaper syscall than fchmod(2). Since
ctime resolution is only in seconds on most filesystems (and
Ruby can only get to seconds AFAIK), we can avoid fchmod(2)
happening within the same second. This allows us to cheat on
synthetic benchmarks where performance is measured in
requests-per-second and not seconds-per-request :)
Secondly, cleanup the acceptor loop and avoid nested
begins/loops as much as possible. If we got ECONNABORTED, then
there's no way the client variable would've been set correctly,
either. If there was something there, then it is at the mercy
of the garbage collector because a method can't both return a
value and raise an exception.