语法: co = coroutine.running()
环境: rewrite_by_lua, access_by_lua*, content_by_lua*, init_by_lua*, ngx.timer., header_filter_by_lua, body_filter_by_lua**
与标准的 Lua coroutine.running API 相同。
该 API 在 init_by_lua* 的环境中可用，是从 0.9.2 开始的。
该 API 在 v0.6.0 版本首次引入。
English source:
syntax: co = coroutine.running()
context: rewrite_by_lua, access_by_lua*, content_by_lua*, init_by_lua*, ngx.timer., header_filter_by_lua, body_filter_by_lua**
Identical to the standard Lua coroutine.running API.
This API was first usable in the context of init_by_lua* since the 0.9.2.
This API was first enabled in the v0.6.0 release.