https://blog.wongcw.com/2018/12/08/%e4%bd%bf%e7%94%a8-loader-helper-%e5%ae%89%e8%a3%85%e5%90%91%e5%af%bc%e5%ae%89%e8%a3%85-swoole-loader-%e6%89%a9%e5%b1%95/