mod_ping_muc: Delay ping a configurable amount of time If a server is restarting, checking immediately before it has a chance to complete its restart and get ready would often fail, preventing the possibility of transparent restarts as supported by Prosody's mod_muc. Reconnecting immediately when a connection is closed for being idle, or because the remote server is trying to reclaim some resources, is also counter-productive as the connection may fail. Also, if there is some Internet routing problem affecting s2s, it may help to wait a bit before checking, in case the problem resolved itself in the mean time.

Over the years, some servers stop working for various reasons, and leave
behind broken roster subscriptions that trigger failing s2s connections.
This module allows cleaning up such cases by unsubscribing local users
from their contacts on those servers. Also works for typos and the like.
Use with care.

```lua
Component "gmail.com" "unsubscriber"
```