For deployments that have https://hg.prosody.im/trunk/file/tip/plugins/muc/register.lib.lua#l7 and use https://modules.prosody.im/mod_muc_http_auth.html users can still register to a MUC even if they are not allowed to join. That means they would receive RAI or RMN, for instance.

This module logs events where more than a certain amount of CPU time was
spent.

``` lua
log_cpu_threshold = 0.01 -- in seconds, so this is 10 milliseconds
```

Uses the Lua
[`os.clock()`](http://www.lua.org/manual/5.2/manual.html#pdf-os.clock)
function to estimate CPU usage.