Multiset<Multiset<?>> multiset = HashMultiset.create();
    multiset.add(multiset, 2);
    Multiset<Multiset<?>> copy = SerializableTester.reserialize(multiset);
    assertEquals(2, copy.size());
    assertSame(copy, copy.iterator().next());
  }

  @J2ktIncompatible
  @GwtIncompatible // Only used by @GwtIncompatible code
  private static class MultisetHolder implements Serializable {
    private final Multiset<?> member;

    int copyIntoArray(@Nullable Object[] dst, int offset) {
      return entries.copyIntoArray(dst, offset);
    }

    @Override
    public UnmodifiableIterator<Entry<K, V>> iterator() {
      return entries.iterator();
    }

    @Override
    @GwtIncompatible("Spliterator")
    public Spliterator<Entry<K, V>> spliterator() {
      return entries.spliteratorWithCharacteristics(SPLITERATOR_CHARACTERISTICS);

  }

  protected K getKeyForNullValue() {
    return getEntryNullReplaces().getKey();
  }

  private Entry<K, V> getEntryNullReplaces() {
    Iterator<Entry<K, V>> entries = getSampleElements().iterator();
    for (int i = 0; i < getNullLocation(); i++) {
      entries.next();
    }
    return entries.next();
  }

  /**

  public void testDescendingNavigation() {
    List<Entry<E>> ascending = new ArrayList<>();
    Iterators.addAll(ascending, sortedMultiset.entrySet().iterator());
    List<Entry<E>> descending = new ArrayList<>();
    Iterators.addAll(descending, sortedMultiset.descendingMultiset().entrySet().iterator());
    Collections.reverse(descending);
    assertEquals(ascending, descending);
  }

        // Tree handle is released after close
        verify(tree, atLeastOnce()).release();
    }

    @Test
    @DisplayName("open(): server returns NO_SUCH_FILE after receiving response -> iterator empty, closed")
    void openHandlesNoSuchFileGracefully() throws Exception {
        when(tree.send(any(Trans2FindFirst2.class), any(Trans2FindFirst2Response.class))).thenAnswer((InvocationOnMock inv) -> {

        }

        @Override
        public boolean contains(final Object o) {
            return parent.contains(o);
        }

        @Override
        public Iterator<E> iterator() {
            return parent.iterator();
        }

        @Override
        public Object[] toArray() {
            return parent.toArray();
        }

        @Override

          .put(CharSink.class, NullByteSink.INSTANCE.asCharSink(UTF_8))
          // All collections are immutable empty. So safe for any type parameter.
          .put(Iterator.class, ImmutableSet.of().iterator())
          .put(PeekingIterator.class, peekingIterator(ImmutableSet.of().iterator()))
          .put(ListIterator.class, ImmutableList.of().listIterator())
          .put(Iterable.class, ImmutableSet.of())

    }
    return (node == header || !range.contains(node.getElement())) ? null : node;
  }

  @Override
  Iterator<E> elementIterator() {
    return Multisets.elementIterator(entryIterator());
  }

  @Override
  Iterator<Entry<E>> entryIterator() {
    return new Iterator<Entry<E>>() {
      @Nullable AvlNode<E> current = firstNode();
      @Nullable Entry<E> prevEntry;

      @Override

      if (result == null) result = ArrayList(2)
      result.add(value(i))
    }
  }
  return result?.unmodifiable().orEmpty()
}

internal fun Headers.commonIterator(): Iterator<Pair<String, String>> = Array(size) { name(it) to value(it) }.iterator()

internal fun Headers.commonNewBuilder(): Headers.Builder {
  val result = Headers.Builder()
  result.namesAndValues += namesAndValues
  return result
}

import com.google.common.base.Predicate;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.WeakOuter;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**