PHP中的Queue，Worker Pool，Coroutine以及爬虫

[Background jobs with php and resque](http://kamisama.me/2012/10/09/background-jobs-with-php-and-resque-part-1-introduction/)

[guzzle PHP并发请求](http://docs.guzzlephp.org/en/latest/quickstart.html#concurrent-requests)

[在PHP中使用协程实现多任务调度](http://www.laruence.com/2015/05/28/3038.html)

[PHP SplQueue 队列简介](http://blog.csdn.net/wuxing26jiayou/article/details/51887665)

[php协程（Coroutine）学习笔记](http://blog.csdn.net/gavin_new/article/details/54603490)

[纯 PHP 开发的并行抓取工具](https://github.com/hightman/pspider)

[Swoole：Redefined PHP Program Language](http://www.swoole.com/)

[phpspider开发文档](https://doc.phpspider.org/)

[Goutte, a simple PHP Web Scraper](https://github.com/FriendsOfPHP/Goutte)

[php-resque: PHP Resque Worker (and Enqueue)](https://github.com/chrisboulton/php-resque)