We've run into a few issues caused by various types of "leak" - e.g. failure to close an iterator, failure to decrement a ref count, which can create a resource leak (file, memory, etc.).

It would be nice to have some general mechanism for asserting that an iterator / DB is closed. This is especially useful in testing (both unit and metamorphic tests).

I'm thinking of something like we have already in Cockroach - a defer that runs a leak check (example). The UX could be improved there, but that might be a good starting point.

Jira issue: PEBBLE-140