cert

the file output bot supports message_with_type, but the docs don't mention it.

All output bots using OutputBot.export_event support the same parameters, the docs could have a section on those and then these bots' docs just refer to the section

It would allow us to better track down bugs where all resources aren't cleaned up correctly (like in #158)

Seems like the only way of doing it is to call len over https://docs.min.io/docs/python-client-api-reference.html#list_objects - we'd have to check if this won't become a bottleneck when there are lots of objects