compatibility guarantee. We have a goal to make this easier to use in the future.


## Where does it come from?

`apiserver` is synced from https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apiserver.
Code changes are made in that location, merged into `k8s.io/kubernetes` and later synced here.


## Things you should *NOT* do

	ctl := memory.NewController(store)

	ctl.RegisterHasSyncedHandler(func() bool {
		return atomic.LoadInt32(&v) > 0
	})

	if ctl.HasSynced() {
		t.Error("has synced but should not")
	}
	atomic.StoreInt32(&v, 1)
	if !ctl.HasSynced() {
		t.Error("has not synced but should")
	}

	// Added as a member to the struct to allow injection for testing.
	servicesSynced cache.InformerSynced

	// podLister is able to list/get pods and is populated by the
	// shared informer passed to NewController
	podLister corelisters.PodLister
	// podsSynced returns true if the pod shared informer has been synced at least once.

		want    string
	}{
		{
			desc: "nil error",
			err:  nil,
			metrics: []string{
				"root_ca_cert_publisher_sync_total",
			},
			want: `
# HELP root_ca_cert_publisher_sync_total [ALPHA] Number of namespace syncs happened in root ca cert publisher.
# TYPE root_ca_cert_publisher_sync_total counter
root_ca_cert_publisher_sync_total{code="200"} 1
				`,
		},
		{
			desc: "kube api error",

	if !c.shouldMirror(endpoints) {
		logger.V(5).Info("Skipping mirroring", "endpoints", klog.KObj(endpoints))
		return
	}
	c.queueEndpoints(obj)
}

// onEndpointSliceAdd queues a sync for the relevant Endpoints resource for a
// sync if the EndpointSlice resource version does not match the expected
// version in the endpointSliceTracker.
func (c *Controller) onEndpointSliceAdd(obj interface{}) {

		return false
	}
	defer ec.queue.Done(key)

	err := ec.syncFn(key)
	if err == nil {
		ec.queue.Forget(key)
		return true
	}

	utilruntime.HandleError(fmt.Errorf("%v failed with: %v", key, err))
	ec.queue.AddRateLimited(key)

	return true
}

// sync is used to turn CRDs into the Established state.
func (ec *EstablishingController) sync(key string) error {
	cachedCRD, err := ec.crdLister.Get(key)

apiVersion: release-notes/v2
kind: bug-fix
area: traffic-management

releaseNotes:
- |

 * and keeping in sync with the system wall clock so that time values make sense in comparison with the system wall clock,
 * including timestamps generated from other processes.
 * <p>
 * This clock effectively measures time by duration (according to System.nanoTime()),
 * in between syncs with the system wall clock.
 * When issuing the first timestamp after the sync interval has expired,

			Name:           "sync_total",
			Help:           "Number of namespace syncs happened in root ca cert publisher.",
			StabilityLevel: metrics.ALPHA,
		},
		[]string{"code"},
	)
	syncLatency = metrics.NewHistogramVec(
		&metrics.HistogramOpts{
			Subsystem:      RootCACertPublisher,
			Name:           "sync_duration_seconds",
			Help:           "Number of namespace syncs happened in root ca cert publisher.",

	// HasSynced returns true once the queue has synced.
	// Syncing indicates that all items in the queue *before* Run was called have been processed.
	HasSynced() bool
}

type queueImpl struct {
	delay     time.Duration
	tasks     []*queueTask
	cond      *sync.Cond
	closing   bool
	closed    chan struct{}
	closeOnce *sync.Once
	// initialSync indicates the queue has initially "synced".
	initialSync *atomic.Bool
	id          string