The storage a backend provides. It only keeps rows; every rule about which event wins lives in createEventCache, so all backends behave the same.
Insert events, ignoring ids already present.
Events matching one filter. Honouring limit is an optimisation; the caller applies it again.
limit
Remove events by id.
The storage a backend provides. It only keeps rows; every rule about which event wins lives in createEventCache, so all backends behave the same.