"foo2": "bar2",
		"foo3": "bar3",
	}

	cases := []struct {
		labels     map[string]string
		labelKey   string
		labelValue string
		want       map[string]string
	}{
		{
			labels: labels,
			want:   labels,
		},
		{
			labels:     labels,
			labelKey:   "foo4",
			labelValue: "42",
			want: map[string]string{
				"foo1": "bar1",
				"foo2": "bar2",
				"foo3": "bar3",
				"foo4": "42",
			},

		lv := slices.Map(f.attrs, func(e attribute.KeyValue) LabelValue {
			return LabelValue{e}
		})
		rh.OnRecord(f.name, lv, value)
	}
	recordHookMutex.RUnlock()
}

func (f baseMetric) Register() error {
	return nil
}

func (f baseMetric) RecordInt(value int64) {
	f.rest.Record(float64(value))
}

func rebuildAttributes(bm baseMetric, labelValues []LabelValue) ([]attribute.KeyValue, attribute.Set) {

	}

	cases := []struct {
		labels     map[string]string
		labelKey   string
		labelValue string
		want       map[string]string
	}{
		{
			labels: labels,
			want:   labels,
		},
		{
			labels:     labels,
			labelKey:   "foo4",
			labelValue: "89",
			want: map[string]string{
				"foo1": "bar1",
				"foo2": "bar2",
				"foo3": "bar3",
				"foo4": "89",
			},

func CloneSelectorAndAddLabel(selector *LabelSelector, labelKey, labelValue string) *LabelSelector {
	if labelKey == "" {
		// Don't need to add a label.
		return selector
	}

	// Clone.
	newSelector := selector.DeepCopy()

	if newSelector.MatchLabels == nil {
		newSelector.MatchLabels = make(map[string]string)
	}

	newSelector.MatchLabels[labelKey] = labelValue

	return newSelector
}

func CloneAndAddLabel(labels map[string]string, labelKey, labelValue string) map[string]string {
	if labelKey == "" {
		// Don't need to add a label.
		return labels
	}
	// Clone.
	newLabels := map[string]string{}
	for key, value := range labels {
		newLabels[key] = value
	}
	newLabels[labelKey] = labelValue
	return newLabels
}

	key attribute.Key
}

// Value creates a new LabelValue for the Label.
func (l Label) Value(value string) LabelValue {
	return LabelValue{l.key.String(value)}
}

// A LabelValue represents a Label with a specific value. It is used to record
// values for a Metric.
type LabelValue struct {
	keyValue attribute.KeyValue
}

func (l LabelValue) Key() Label {
	return Label{l.keyValue.Key}
}

func Label(ctx context.Context, key string) (string, bool) {
	ctxLabels := labelValue(ctx)
	v, ok := ctxLabels[key]
	return v, ok
}

// ForLabels invokes f with each label set on the context.
// The function f should return true to continue iteration or false to stop iteration early.
func ForLabels(ctx context.Context, f func(key, value string) bool) {
	ctxLabels := labelValue(ctx)
	for k, v := range ctxLabels {
		if !f(k, v) {
			break

func (dm *disabledMetric) RecordInt(value int64) {}

// Register implements Metric
func (dm *disabledMetric) Register() error {
	return nil
}

// With implements Metric
func (dm *disabledMetric) With(labelValues ...LabelValue) Metric {
	return dm
}

		// ~ is used in other portions of the API, reserve it with special meaning although it's unlikely to be documented
		if labelValue == "none" || labelValue == "~" || strings.HasSuffix(labelValue, "/none") {
			return nil, true
		}
		namespacedName := strings.Split(labelValue, "/")
		switch len(namespacedName) {
		case 1:
			return &krt.Named{
				Name:      namespacedName[0],
				Namespace: defaultNamespace,

	return d.name
}

func (d *derivedGauge) Register() error {
	return nil
}

func (d *derivedGauge) ValueFrom(valueFn func() float64, labelValues ...LabelValue) DerivedMetric {
	d.mu.Lock()
	defer d.mu.Unlock()
	lv := slices.Map(labelValues, func(e LabelValue) attribute.KeyValue {
		return e.keyValue
	})
	as := attribute.NewSet(lv...)
	d.attrs[as] = valueFn
	return d