We sometimes need to do some in-memory only stuff, e.g., to check if
GC is already running for a datastore, which is a try_lock on a mutex
that is in-memory.
Actually the whole thing would be nicer if we could guarantee to hold
the correct contract statically, e.g., like
https://docs.rust-embedded.org/book/static-guarantees/design-contracts.html
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>