logger.Info("bucketMetacache.findCache: bucket %s does not match this bucket %s", o.Bucket, b.bucket)
		debug.PrintStack()
		return metacache{}
	}

	// Grab a write lock, since we create one if we cannot find one.
	b.mu.Lock()
	defer b.mu.Unlock()

	// Check if exists already.
	if c, ok := b.caches[o.ID]; ok {
		c.lastHandout = time.Now()
		b.caches[o.ID] = c
		b.debugf("returning existing %v", o.ID)
		return c

type IAMStorageAPI interface {
	// The role of the read-write lock is to prevent go routines from
	// concurrently reading and writing the IAM storage. The (r)lock()
	// functions return the iamCache. The cache can be safely written to
	// only when returned by `lock()`.
	lock() *iamCache
	unlock()
	rlock() *iamCache
	runlock()
	getUsersSysType() UsersSysType

	if err == nil {
		return
	}

	nerr := unwrapErrs(err)
	l.Lock()
	shouldLog := true
	prev, ok := l.IDMap[id]
	if !ok {
		l.IDMap[id] = onceErr{
			Err:   nerr,
			Count: 1,
		}
	} else if prev.Err.Error() == nerr.Error() {
		// if errors are equal do not log.
		prev.Count++
		l.IDMap[id] = prev
		shouldLog = false
	}
	l.Unlock()

	if shouldLog {
		consoleLogIf(ctx, subsystem, err, errKind...)
	}

func (r *ReqInfo) AppendTags(key, val string) *ReqInfo {
	if r == nil {
		return nil
	}
	r.Lock()
	defer r.Unlock()
	r.tags = append(r.tags, KeyVal{key, val})
	return r
}

// SetTags - sets key/val to ReqInfo.tags
func (r *ReqInfo) SetTags(key, val string) *ReqInfo {
	if r == nil {
		return nil
	}
	r.Lock()
	defer r.Unlock()
	// Search of tag key already exists in tags
	var updated bool
	for _, tag := range r.tags {

	return &targetsList{}
}

func (tl *targetsList) get() []Target {
	tl.mu.RLock()
	defer tl.mu.RUnlock()

	return tl.list
}

func (tl *targetsList) add(t Target) {
	tl.mu.Lock()
	defer tl.mu.Unlock()

	tl.list = append(tl.list, t)
}

func (tl *targetsList) set(tgts []Target) {
	tl.mu.Lock()
	defer tl.mu.Unlock()

	tl.list = tgts
}

var (

	globalAuthPluginMutex.Lock()
	defer globalAuthPluginMutex.Unlock()
	return globalAuthNPlugin
}

func newGlobalAuthZPluginFn() *polplugin.AuthZPlugin {
	globalAuthPluginMutex.Lock()
	defer globalAuthPluginMutex.Unlock()
	return globalAuthZPlugin
}

func setGlobalAuthNPlugin(authn *idplugin.AuthNPlugin) {
	globalAuthPluginMutex.Lock()
	globalAuthNPlugin = authn

	defer func() {
		if unlockOnDefer {
			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := z.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()
		nsUnlocker = func() { lock.RUnlock(lkctx) }
		unlockOnDefer = true
	}

	checkPrecondFn := opts.CheckPrecondFn

func (m *bucketMeasurement) updateExponentialMovingAverage(endTime time.Time) {
	// Calculate aggregate avg bandwidth and exp window avg
	m.lock.Lock()
	defer func() {
		m.startTime = endTime
		m.lock.Unlock()
	}()

	if m.startTime.IsZero() {
		return
	}

	if endTime.Before(m.startTime) {
		return
	}

	duration := endTime.Sub(m.startTime)

  }

  @Benchmark
  void unorderedCycleDetectingLocks(int reps) {
    lockAndUnlock(factory.newReentrantLock("foo"), reps);
  }

  private static void lockAndUnlock(Lock lock, int reps) {
    for (int i = 0; i < reps; i++) {
      lock.lock();
      lock.unlock();
    }
  }

  @Benchmark
  void orderedPlainLocks(int reps) {
    lockAndUnlockNested(plainLocks, reps);
  }

  @Benchmark

		t.Fatalf("unexpected error: %v", err)
	}
	if err := ps.Subscribe(MaskAll, ch2, doneCh, nil); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	ps.Lock()
	defer ps.Unlock()

	if len(ps.subs) != 2 || ps.NumSubscribers(MaskAll) != 2 || ps.Subscribers() != 2 {
		t.Fatalf("expected 2 subscribers")
	}
}

func TestNumSubscribersMask(t *testing.T) {
	ps := New[Maskable, Mask](2)