@Override
                public Iterator<Entry<String, String>> iterator() {
                  return new Iterator<Entry<String, String>>() {

                    final Iterator<Entry<String, String>> iterator = map.entrySet().iterator();

                    @Override
                    public void remove() {
                      iterator.remove();
                    }

    }

    @Override
    public SortedMultiset<E> descendingMultiset() {
      return new StandardDescendingMultiset() {

        @Override
        Iterator<Entry<E>> entryIterator() {
          return backingMultiset.descendingMultiset().entrySet().iterator();
        }
      };
    }

    @Override
    public NavigableSet<E> elementSet() {
      return new StandardElementSet();
    }

    @Override

  public void testRemoveAtIndexConcurrentWithIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<E> iterator = collection.iterator();
          getList().remove(getNumElements() / 2);
          iterator.next();
        });
  }

  @ListFeature.Require(SUPPORTS_REMOVE_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveAtIndex_last() {

import java.io.InputStream;
import java.util.Iterator;
import org.jspecify.annotations.Nullable;

/**
 * An {@link InputStream} that concatenates multiple substreams. At most one stream will be open at
 * a time.
 *
 * @author Chris Nokleberg
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
final class MultiInputStream extends InputStream {

  private final Iterator<? extends ByteSource> it;

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

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

  public List<E> asList() {
    return Arrays.asList(e0(), e1(), e2(), e3(), e4());
  }

  public static class Strings extends SampleElements<String> {
    public Strings() {

        assertThat(lru.get("aaa"), is("111"));
        Iterator<String> i = lru.keySet().iterator();
        assertThat(i.next(), is("bbb"));
        assertThat(i.next(), is("ccc"));
        assertThat(i.next(), is("aaa"));
        lru.put("ddd", "444");
        assertThat(lru.size(), is(3));
        assertThat(lru.get("bbb"), is(nullValue()));
        i = lru.keySet().iterator();
        assertThat(i.next(), is("ccc"));

  }

  /**
   * A sensible default implementation of {@link #iterator}, in terms of {@link #listIterator()}. If
   * you override {@link #listIterator()}, you may wish to override {@link #iterator} to forward to
   * this implementation.
   *
   * @since 7.0
   */
  protected Iterator<E> standardIterator() {
    return listIterator();
  }

  /**

     */
    public CaseInsensitiveSet(final int initialCapacity) {
        map = new CaseInsensitiveMap<>(initialCapacity);
    }

    @Override
    public Iterator<String> iterator() {
        return map.keySet().iterator();
    }

    @Override
    public int size() {
        return map.size();
    }

    @Override
    public boolean isEmpty() {
        return map.isEmpty();
    }

    return delegate.higher(checkValid(e));
  }

  @Override
  public boolean isEmpty() {
    return delegate.isEmpty();
  }

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

  @Override
  public E last() {
    return delegate.last();
  }

  @Override
  public @Nullable E lower(E e) {
    return delegate.lower(checkValid(e));
  }

    assertEqualInOrder(expected, multimap().values());
  }

  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  @CollectionSize.Require(ONE)
  public void testValuesIteratorRemove() {
    Iterator<V> valuesItr = multimap().values().iterator();
    valuesItr.next();
    valuesItr.remove();
    assertTrue(multimap().isEmpty());
  }