======  php多进程初探—-进程间通信二三事======
https://www.bookstack.cn/read/advanced-php/8.%20php%E5%A4%9A%E8%BF%9B%E7%A8%8B%E5%88%9D%E6%8E%A2---%E8%BF%9B%E7%A8%8B%E9%97%B4%E9%80%9A%E4%BF%A1%E4%BA%8C%E4%B8%89%E4%BA%8B.md