code: func (st *Store) PeriodicCleanup(interval time.Duration, quit <-chan struct{}) {
  	t := time.NewTicker(interval)
  	defer t.Stop()
  	for {
  		select {
  		case <-t.C:
  			st.Cleanup()
  		case <-quit:
  			return
  		}
  	}
  }
docs: // PeriodicCleanup runs Cleanup every interval. Close quit channel to stop.