Fingerprint of the logical command payload.
Client-provided idempotency key.
Operation namespace, usually a use-case or route name.
OptionalreservationTime-to-live for unfinished work before a successor may reserve the key.
OptionalscopeLogical scope for this key.
OptionalttlOptional time-to-live for the completed replay result.
Input for reserving an idempotency key.