OptionalwithOptional cross-process lease, for a store that several processes share. When present, the token manager runs every refresh inside it and reads the stored token again once the lease is held, so a refresh token that another process has already spent is never sent to SSO a second time.
fn must not start until no other holder of the lease for this store is
running, and the lease must be released when fn settles, whether it
resolves or rejects. get, set and delete called from inside fn
must not wait for the lease, and get must return what the last holder
wrote rather than a cached copy. Adapters without this method behave as
single-process stores.
Persistence contract for StoredToken records, keyed by character id.
Implementations must return copies rather than shared references and must tolerate
get/deletefor ids they have never seen.