*/
  private static <B extends @Nullable Object> Entry<Class<? extends @NonNull B>, B> checkedEntry(
      Entry<Class<? extends @NonNull B>, B> entry) {
    return new ForwardingMapEntry<Class<? extends @NonNull B>, B>() {
      @Override
      protected Entry<Class<? extends @NonNull B>, B> delegate() {
        return entry;
      }

      @Override
      @ParametricNullness

    TestMap<K, V> inner = new TestMap<>(innermost, mutex);
    NavigableMap<K, V> outer = Synchronized.navigableMap(inner, mutex);
    return outer;
  }

  static class TestEntry<K, V> extends ForwardingMapEntry<K, V> implements Serializable {
    private final Entry<K, V> delegate;
    private final Object mutex;

    TestEntry(Entry<K, V> delegate, Object mutex) {
      this.delegate = delegate;
      this.mutex = mutex;

          backingRowMap.entrySet().spliterator(),
          Spliterator.DISTINCT | Spliterator.NONNULL,
          this::wrapEntry);
    }

    Entry<C, V> wrapEntry(Entry<C, V> entry) {
      return new ForwardingMapEntry<C, V>() {
        @Override
        protected Entry<C, V> delegate() {
          return entry;
        }

        @Override
        public V setValue(V value) {

        return new TransformedIterator<Entry<K, V>, Entry<K, V>>(filteredEntrySet.iterator()) {
          @Override
          Entry<K, V> transform(Entry<K, V> entry) {
            return new ForwardingMapEntry<K, V>() {
              @Override
              protected Entry<K, V> delegate() {
                return entry;
              }

              @Override
              @ParametricNullness

        return new TransformedIterator<Entry<K, V>, Entry<K, V>>(filteredEntrySet.iterator()) {
          @Override
          Entry<K, V> transform(Entry<K, V> entry) {
            return new ForwardingMapEntry<K, V>() {
              @Override
              protected Entry<K, V> delegate() {
                return entry;
              }

              @Override
              @ParametricNullness