### Feature

- Add indexer for storage cacher ([#85445](https://github.com/kubernetes/kubernetes/pull/85445), [@shaloulcy](https://github.com/shaloulcy)) [SIG API Machinery]

 * @param <T> the element type
 * @see IndexedIterator
 */
public class Indexed<T> {

    /** The element. */
    private final T element;

    /** The index of the element. */
    private final int index;

    /**
     * Constructor.
     *
     * @param element the element
     * @param index the index of the element
     */
    public Indexed(final T element, final int index) {
        this.element = element;

- Fix indexer bug that resulted in incorrect index updates if number of index values for a given object was changing during update ([#109137](https://github.com/kubernetes/kubernetes/pull/109137), [@wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery]

    // requireNonNull is safe because we use indexes that were populated by the constructor.
    V value = requireNonNull(values[rowIndex][columnIndex]);
    return cellOf(rowKey, columnKey, value);
  }

  @Override
  V getValue(int index) {
    // requireNonNull is safe because we use indexes that were populated by the constructor.

)

// a bucketMetacache keeps track of all caches generated
// for a bucket.
type bucketMetacache struct {
	// Name of bucket
	bucket string

	// caches indexed by id.
	caches map[string]metacache
	// cache ids indexed by root paths
	cachesRoot map[string][]string `msg:"-"`

	// Internal state
	mu      sync.RWMutex `msg:"-"`
	updated bool         `msg:"-"`
}

type deleteAllStorager interface {

    // requireNonNull is safe because we use indexes that were populated by the constructor.
    V value = requireNonNull(values[rowIndex][columnIndex]);
    return cellOf(rowKey, columnKey, value);
  }

  @Override
  V getValue(int index) {
    // requireNonNull is safe because we use indexes that were populated by the constructor.

   * reported {@link Spliterator#SUBSIZED}. This is generally the case if the underlying stream
   * comes from a data structure supporting efficient indexed random access, typically an array or
   * list.
   *
   * <p>The order of the resulting stream is defined if and only if the order of the original stream
   * was defined.
   */

 *
 * List<String> list = ...;
 * for (Indexed<String> indexed : indexed(list)) {
 *     System.out.println(indexed.getIndex());
 *     System.out.println(indexed.getElement());
 * }
 * </pre>
 *
 * <pre>
 * import static org.codelibs.core.collection.IndexedIterator.*;
 * import static org.codelibs.core.io.LineIterator.*;
 *
 * BufferedReader reader = ...;
 * for (Indexed&lt;String&gt; indexed : indexed(iterable(reader))) {

     * @throws IllegalArgumentException if {@code indexes} is empty
     */
    public ScaleAndIndexes indexes(int... indexes) {
      return new ScaleAndIndexes(scale, indexes.clone());
    }

    /**
     * Specifies multiple quantile indexes to be calculated, each index being the k in the kth
     * q-quantile.
     *
     * @param indexes the quantile indexes, each of which must be in the inclusive range [0, q] for

   * reported {@link Spliterator#SUBSIZED}. This is generally the case if the underlying stream
   * comes from a data structure supporting efficient indexed random access, typically an array or
   * list.
   *
   * <p>The order of the resulting stream is defined if and only if the order of the original stream
   * was defined.
   */