util.async: Improve debug logging in a few places
Knowing the state of the coroutine as well as the runner state can be helpful.
For full information on our dependencies, version requirements, and
where to find them, see https://prosody.im/doc/depends
If you have luarocks available on your platform, install the following:
- luaexpat
- luasocket
- luafilesystem
- luasec