histogram: prometheus.NewHistogramVec(prometheus.HistogramOpts{
		Name:    "tier_ttlb_seconds",
		Help:    "Time taken by requests served by warm tier",
		Buckets: []float64{0.01, 0.1, 1, 2, 5, 10, 60, 5 * 60, 15 * 60, 30 * 60},
	}, []string{"tier"}),
}

func (t *tierMetrics) Observe(tier string, dur time.Duration) {
	t.histogram.With(prometheus.Labels{"tier": tier}).Observe(dur.Seconds())
}

			wg.Wait()

			// Reset for the next interval
			timer.Reset(globalAPIConfig.getDeleteCleanupInterval())
		}
	}
}

func (s *erasureSets) cleanupStaleUploads(ctx context.Context) {
	timer := time.NewTimer(globalAPIConfig.getStaleUploadsCleanupInterval())
	defer timer.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-timer.C:
			var wg sync.WaitGroup
			for _, set := range s.sets {

			return
		}

		op := auditTierOp{
			Tier:        tier,
			OutputBytes: bytes,
		}

		if err == nil {
			since := time.Since(startTime)
			op.TimeToResponseNS = since.Nanoseconds()
			globalTierMetrics.Observe(tier, since)
			globalTierMetrics.logSuccess(tier)
		} else {
			op.Error = err.Error()
			globalTierMetrics.logFailure(tier)
		}

                    BlockFetcher block_fetcher,
                    std::function<uint64_t()> timer_seconds = TF_NowSeconds)
      : block_size_(block_size),
        max_bytes_(max_bytes),
        max_staleness_(max_staleness),
        block_fetcher_(block_fetcher),
        timer_seconds_(timer_seconds),
        pruning_thread_(nullptr,
                        [](TF_Thread* thread) { TF_JoinThread(thread); }) {

		}
		if maxWait > 0 && wantSleep > maxWait {
			wantSleep = maxWait
		}
		timer := time.NewTimer(wantSleep)
		select {
		case <-ctx.Done():
			if !timer.Stop() {
				<-timer.C
				if d.isScanner {
					globalScannerMetrics.incTime(scannerMetricYield, wantSleep)
				}
			}
			return
		case <-timer.C:
			if d.isScanner {
				globalScannerMetrics.incTime(scannerMetricYield, wantSleep)

		defer cancel()
		dm.Unlock(ctx)
		unlockReturned <- struct{}{}
	}()

	timer := time.NewTimer(2 * testDrwMutexUnlockCallTimeout)
	defer timer.Stop()

	select {
	case <-unlockReturned:
		t.Fatal("Unlock timed out, which should not happen")
	case <-timer.C:
	}
}

// Borrowed from mutex_test.go
func HammerMutex(m *DRWMutex, loops int, cdone chan bool) {

      producer.beganProducing.await();

      // make sure we time out
      Stopwatch timer = Stopwatch.createStarted();

      int drained = drain(q, newArrayList(), 2, 10, MILLISECONDS, interruptibly);
      assertThat(drained).isAtMost(1);

      assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);

      producer.beganProducing.await();

      // make sure we time out
      Stopwatch timer = Stopwatch.createStarted();

      int drained = drain(q, newArrayList(), 2, 10, MILLISECONDS, interruptibly);
      assertThat(drained).isAtMost(1);

      assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);

import org.codelibs.core.timer.TimeoutManager;
import org.codelibs.core.timer.TimeoutTask;
import org.codelibs.fess.Constants;
import org.codelibs.fess.crawler.client.FesenClient;
import org.codelibs.fess.es.client.SearchEngineClient;
import org.codelibs.fess.exception.ContainerNotAvailableException;
import org.codelibs.fess.helper.SuggestHelper;
import org.codelibs.fess.timer.SystemMonitorTarget;

		adminRouter.Methods(http.MethodGet).Path(adminVersion + "/tier/{tier}").HandlerFunc(adminMiddleware(adminAPI.VerifyTierHandler))
		// Tier stats
		adminRouter.Methods(http.MethodGet).Path(adminVersion + "/tier-stats").HandlerFunc(adminMiddleware(adminAPI.TierStatsHandler))

		// Cluster Replication APIs