idalloc

type Allocator interface {
	// Allocate allocates a timestamp.
	Allocate(ctx context.Context) (uint64, error)

	// BarrierUtil make a barrier, next allocate call will generate id greater than barrier.
	BarrierUntil(ctx context.Context, barrier uint64) error

	// Sync expire the local allocator messages,
	// syncs the local allocator and remote allocator.
	Sync()

	// SyncIfExpired syncs the local allocator and remote allocator if the duration since last sync operation is greater than expire.
	SyncIfExpired(expire time.Duration)
}