mod_smacks: Destroy timed out session in async context (fixes #1884) Prevents ASYNC-01 due to storage interactions in a timer. Also considered modifying mod_c2s to allow passing arbitrary closures into its runner thread but this seems like a big step away from the current code for just this module. Also considered creating a dedicated runner in mod_smacks, but ensuring continuity across module reloads might be tricky. We could further improve this in the next major version.