ThreadPool - an implementation that doesn't waste CPU resources

GEM MERGED INTO THREAD, THIS IS UNMAINTAINED NOW: https://github.com/meh/ruby-thread

All the implementations I looked at were either buggy or wasted CPU resources for no apparent reason, for example used a sleep of 0.01 seconds to then check for readiness and stuff like this.

This implementation uses standard locking functions to work properly across multiple Ruby implementations.

Example

require 'threadpool'

pool = ThreadPool.new(4)

0.upto(10) { pool.process { sleep 2; puts 'lol' } }

gets # otherwise the program ends without the pool doing anything

You should get 4 lols every 2 seconds.