ThreadPool

ThreadPool 實作
http://columns.chicken-house.net/2007/12/14/threadpool-%E5%AF%A6%E4%BD%9C-1-%E5%9F%BA%E6%9C%AC%E6%A6%82%E5%BF%B5/
http://columns.chicken-house.net/2007/12/17/threadpool-%E5%AF%A6%E4%BD%9C-2-%E7%A8%8B%E5%BC%8F%E7%A2%BC-c/

http://openhome.cc/Gossip/DesignPattern/ThreadPool.htm
http://openhome.cc/Gossip/DesignPattern/ThreadPerMessage.htm