resty-etcd 是一个 OpenResty 非堵塞的 etcd 驱动，支持 etcd API v2.
Fetchs Nginx variable by Luajit with FFI way which is fast and cheap.
Apache APISIX 是一个云原生 API 网关
Check the data type for Lua variable
This is Lua-Openresty implementation library base on FFI for libr3.