func (ps *PubSub[T, M]) Subscribe(mask M, subCh chan T, doneCh <-chan struct{}, filter func(entry T) bool) error {
	totalSubs := atomic.AddInt32(&ps.numSubscribers, 1)
	if ps.maxSubscribers > 0 && totalSubs > ps.maxSubscribers {
		atomic.AddInt32(&ps.numSubscribers, -1)
		return fmt.Errorf("the limit of `%d` subscribers is reached", ps.maxSubscribers)
	}
	ps.Lock()
	defer ps.Unlock()

		// Uncomment below to see message appearance:
		// fmt.Println(output)
		switch {
		case testCase.dlURL == "" && output != "":
			t.Errorf("Testcase %d: no newer release available but got an update message: %s", i+1, output)
		case output == "" && testCase.dlURL != "" && testCase.older > 0:
			t.Errorf("Testcase %d: newer release is available but got empty update message!", i+1)
		case output == "" && (testCase.dlURL == "" || testCase.older <= 0):

-----------------
failure for all cases.

// Pseudo code for managing `format.json`.

// Generic checks.
if (no quorum) return error
if (any disk is corrupt) return error // Always error
if (jbod inconsistent) return error // Always error.
if (disks not recognized) // Always error.

// Specific checks.
if (all disks online)
  if (all disks return format.json)
     if (jbod consistent)

	f, err := newFile(path)
	if err != nil {
		return fmt.Errorf("unable to create new file at %v: %w", path, err)
	}

	w.f = f

	return nil
}

// NewDir creates a new concurrency safe Writer which performs log rotation.
func NewDir(opts Options) (io.WriteCloser, error) {
	if err := os.MkdirAll(opts.Directory, os.ModePerm); err != nil {

func GetWebhookRevision(wh admitv1.MutatingWebhookConfiguration) (string, error) {
	if tagName, ok := wh.ObjectMeta.Labels[label.IoIstioRev.Name]; ok {
		return tagName, nil
	}
	return "", fmt.Errorf("could not extract tag revision from webhook")
}

// DeleteTagWebhooks deletes the given webhooks.
func DeleteTagWebhooks(ctx context.Context, client kubernetes.Interface, tag string) error {
	webhooks, err := GetWebhooksWithTag(ctx, client, tag)

	if info.Free > info.Total {
		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

	return ParseWithSpecialTableName(dest, cacheStore, namer, "")
}

// ParseWithSpecialTableName get data type from dialector with extra schema table
func ParseWithSpecialTableName(dest interface{}, cacheStore *sync.Map, namer Namer, specialTableName string) (*Schema, error) {
	if dest == nil {
		return nil, fmt.Errorf("%w: %+v", ErrUnsupportedDataType, dest)
	}

		t.Fatalf("no error should happen when migrate scanner, valuer struct, got error %v", err)
	}

	data := SerializerStruct{}

	if err := DB.Create(&data).Error; err != nil {
		t.Fatalf("failed to create data, got error %v", err)
	}

	var result SerializerStruct
	if err := DB.First(&result, data.ID).Error; err != nil {
		t.Fatalf("failed to query data, got error %v", err)
	}

// ValidateControlPlaneFlags checks arguments for valid values and combinations
func (o *CentralControlPlaneOptions) ValidateControlPlaneFlags() error {
	if o.Xds != "" && o.XdsPodLabel != "" {
		return fmt.Errorf("either --xds-address or --xds-label, not both")
	}
	if o.Plaintext && o.CertDir != "" {
		return fmt.Errorf("either --plaintext or --cert-dir, not both")
	}
	return nil

	if info.Free > info.Total {
		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")