[Ur] howto register cleanup which is neither uw_malloc nor transactional?

[Marc Weber]

This requires two callbacks:
- one for decreasing the usage counter on Ruby objcets (similar to when
  uw_malloc storage is freed)
  (uw_register_transactional or uw_set_global could be abused ?)
- one callback to clear the cache (eg of http requests) after a request
  stops being executed which is called in all cases:
    * retried too often, fatal, or success

How to implement / which existing code to use so that you could accept
the patch ? How would you implement it?

Is there a way to run code on startup ? Eg for loading Ruby modules
thereby proofing that they exist?

Marc Weber