https://engineering.mercari.com/blog/entry/2016-05-25-170108/
https://qiita.com/nobuh/items/40ef50dd70fdf8a580e4
https://techblog.istyle.co.jp/archives/4136
https://blog.wnotes.net/posts/build-openresty-with-opentracing/
https://innossh.hatenablog.com/entry/2017/08/22/223300
https://www.slideshare.net/iosiftakakurayusuke/open-restylua
https://techblog.kayac.com/9_lua-nginx-module_techkayaccom_advent_calendar_2013.html