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
	}

	if !o.Create {

}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat
}

func (t *tierMetrics) logFailure(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.failure++
	t.requestsCount[tier] = stat
}

var (

	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
	globalAuthPluginMutex.Unlock()
}

Returning any error will also cancel the stream remotely.

CAREFUL: When utilizing two-way communication, it is important to ensure that the remote handler is not blocked on a send.
If the remote handler is blocked on a send, and the client is trying to send without the remote receiving, 
the operation would become deadlocked if the channels are full.

### Typed handlers

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)

    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
  void orderedCycleDetectingLocks(int reps) {

type TargetList struct {
	sync.RWMutex
	targets map[TargetID]Target
}

// Add - adds unique target to target list.
func (list *TargetList) Add(targets ...Target) error {
	list.Lock()
	defer list.Unlock()

	for _, target := range targets {
		if _, ok := list.targets[target.ID()]; ok {
			return fmt.Errorf("target %v already exists", target.ID())
		}
		list.targets[target.ID()] = target
	}

	return nil
}

		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)

func (l *Init) Do(f func() error) error {
	if atomic.LoadUint32(&l.done) == 0 {
		return l.do(f)
	}
	return nil
}

func (l *Init) do(f func() error) error {
	l.m.Lock()
	defer l.m.Unlock()
	if atomic.LoadUint32(&l.done) == 0 {
		if err := f(); err != nil {
			return err
		}
		// Mark as done only when f() is successful
		atomic.StoreUint32(&l.done, 1)
	}
	return nil
}

func (c *connMgr) addConn(conn *ZtunnelConnection) {
	log.Debug("ztunnel connected")
	c.mu.Lock()
	defer c.mu.Unlock()
	c.connectionSet[conn] = struct{}{}
	c.latestConn = conn
	ztunnelConnected.RecordInt(int64(len(c.connectionSet)))
}

func (c *connMgr) LatestConn() *ZtunnelConnection {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.latestConn
}

func (c *connMgr) deleteConn(conn *ZtunnelConnection) {