flush

Blocks until all prior writes are durably persisted (survive a process crash).

Autograph calls flush at the points where a lost write would let a sequence number be reused after a crash — every event under SeqPersistence.EveryEvent, and at each chunk boundary/reservation under SeqPersistence.Chunked. The default is a no-op, correct for already-synchronous stores such as InMemorySeqStore.