workers

type Config struct {
	Enabled  bool
	Interval time.Duration
}

type EvictionBackend interface {
	Len() int64
	Mem() int64
	ShouldEvict() (bytes int64, should bool)
	EvictN(n int) (freedBytes, items int64)
}

type EvictorWorker interface {
	// SampleVictims returns up to SxK candidate keys/ids for eviction
	// (already pre-filtered by shard sampling). Implementation must be allocation‑lean.
	SampleVictims(S, K int) []uint64
	// Remove removes a single key. Must revalidate under shard lock internally.
	// Returns freed bytes and whether an item was actually removed.
	Remove(key uint64) (freedBytes int64, removed bool)
}

type LoggerWorker interface {
	Metrics() service.Metrics
	Logs() <-chan service.ServiceLog
}

type MetricsWorker interface {
	SnapshotMetrics() map[string]float64
}

type RefreshBackend interface {
	ScanOutdated() ([64]*model.Entry, bool)
	Refresh(entry *model.Entry) error
}

type RefresherWorker interface {
	// ScanOutdated returns 64 keys that are due for refresh.
	ScanOutdated() ([64]*model.Entry, bool)
	// Refresh fetches the value for a key and atomically swaps it in.
	Refresh(entry *model.Entry) error
}