One row of the instance's idempotency ledger — a caller-supplied
idempotencyKey a state-changing verb already committed under. Recorded in
the same CAS commit as the operation it dedupes, so "the op applied" and
"the key is recorded" can never diverge. Rows expire at expiresAt and are
pruned lazily whenever a later keyed operation commits.
One row of the instance's idempotency ledger — a caller-supplied
idempotencyKeya state-changing verb already committed under. Recorded in the same CAS commit as the operation it dedupes, so "the op applied" and "the key is recorded" can never diverge. Rows expire atexpiresAtand are pruned lazily whenever a later keyed operation commits.