cache := c.(*lruCache[uint64])

	assert.Equal(t, cache.store.Len(), 0)
	assert.Equal(t, cache.indexLength(), 0)

	// adding the entry populates the indexes
	c.Add(firstEntry.Key(), firstEntry, req, res)

	assert.Equal(t, cache.store.Len(), 1)
	assert.Equal(t, cache.indexLength(), 2)
	assert.Equal(t, cache.configIndexSnapshot(), map[ConfigHash]sets.Set[uint64]{

	for i, ik := range iKeys {
		v, ok := l.store.Get(ik)
		if !ok {
			continue
		}

		res[i] = v.value
	}
	return res
}

func (l *lruCache[K]) indexLength() int {
	l.mu.RLock()
	defer l.mu.RUnlock()
	return len(l.configIndex)
}

func (l *lruCache[K]) configIndexSnapshot() map[ConfigHash]sets.Set[K] {
	l.mu.RLock()
	defer l.mu.RUnlock()

		TimeTag: cbor.EncTagNone,

		// Indefinite-length items have multiple encodings and aren't being used anyway, so
		// disable to avoid an opportunity for nondeterminism.
		IndefLength: cbor.IndefLengthForbidden,

		// Preserve distinction between nil and empty for slices and maps.
		NilContainers: cbor.NilContainerAsNull,

		// OK to produce tags.
		TagsMd: cbor.TagsAllowed,

		// is 10000.
		MaxNestedLevels: 64,

		MaxArrayElements: 1024,
		MaxMapPairs:      1024,

		// Indefinite-length sequences aren't produced by this serializer, but other
		// implementations can.
		IndefLength: cbor.IndefLengthAllowed,

		// Accept inputs that contain CBOR tags.
		TagsMd: cbor.TagsAllowed,

		// Decode type 0 (unsigned integer) as int64.