unicorn 4.0.0 - for mythical hardware!

A single Unicorn instance may manage more than 1024 workers
without needing privileges to modify resource limits.  As a
result of this, the "raindrops"[1] gem/library is now a required
dependency.

TCP socket defaults now favor low latency to mimic UNIX domain
socket behavior (tcp_nodelay: true, tcp_nopush: false).  This
hurts throughput, users who want to favor throughput should
specify "tcp_nodelay: false, tcp_nopush: true" in the listen
directive.

Error logging is more consistent and all lines should be
formatted correctly in backtraces.  This may break the
behavior of some log parsers.

The call stack is smaller and thus easier to examine backtraces
when debugging Rack applications.

There are some internal API changes and cleanups, but none that
affect applications designed for Rack.  See "git log v3.7.0.."
for details.

For users who cannot install kgio[2] or raindrops, Unicorn 1.1.x
remains supported indefinitely.  Unicorn 3.x will remain
supported if there is demand.  We expect raindrops to introduce
fewer portability problems than kgio did, however.

[1] http://raindrops.bogomips.org/
[2] http://bogomips.org/kgio/