}

  static <T extends @Nullable Object> Iterator<T> cycle(Iterable<T> iterable) {
    return new Iterator<T>() {
      Iterator<T> iterator = Collections.<T>emptySet().iterator();

      @Override
      public boolean hasNext() {
        return true;
      }

      @Override
      public T next() {
        if (!iterator.hasNext()) {
          iterator = iterable.iterator();
        }

    this.elementOrder = elementOrder;
  }

  @Override
  public int compare(Iterable<T> leftIterable, Iterable<T> rightIterable) {
    Iterator<T> left = leftIterable.iterator();
    Iterator<T> right = rightIterable.iterator();
    while (left.hasNext()) {
      if (!right.hasNext()) {
        return LEFT_IS_GREATER; // because it's longer
      }

    this.elementOrder = elementOrder;
  }

  @Override
  public int compare(Iterable<T> leftIterable, Iterable<T> rightIterable) {
    Iterator<T> left = leftIterable.iterator();
    Iterator<T> right = rightIterable.iterator();
    while (left.hasNext()) {
      if (!right.hasNext()) {
        return LEFT_IS_GREATER; // because it's longer
      }

        if (object == null) {
          throw new NullPointerException();
        }
      }
    }
    return super.containsAll(collection);
  }

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

  @Override
  public @Nullable Object[] toArray() {
    @Nullable Object[] result = new @Nullable Object[contents.length];

    Iterator<Entry<K, V>> entryItr = entrySet.iterator();
    assertEquals(e0(), entryItr.next());
    entryItr.remove();
    assertTrue(getMap().isEmpty());
    assertFalse(entrySet.contains(e0()));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testIteratorRemoveMultiple() {

    Iterator<Entry<K, V>> entryItr = entrySet.iterator();
    assertEquals(e0(), entryItr.next());
    entryItr.remove();
    assertTrue(getMap().isEmpty());
    assertFalse(entrySet.contains(e0()));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testIteratorRemoveMultiple() {

      return standardToString();
    }

    @Override
    public Set<Entry<K, V>> entrySet() {
      return new StandardEntrySet() {
        @Override
        public Iterator<Entry<K, V>> iterator() {
          return delegate().entrySet().iterator();
        }
      };
    }

    @Override
    public void clear() {
      standardClear();
    }

    @Override
    public boolean isEmpty() {

  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<E> iterator = collection.iterator();
          collection.clear();
          iterator.next();
        });
  }

    }

    void setValue(@ParametricNullness V value) {
      checkState(current != null);
      current.setValue(value);
    }
  }

  /** An {@code Iterator} over distinct keys in key head order. */
  private final class DistinctKeyIterator implements Iterator<K> {
    final Set<K> seenKeys = Sets.newHashSetWithExpectedSize(keySet().size());
    @Nullable Node<K, V> next = head;
    @Nullable Node<K, V> current;

import org.jspecify.annotations.Nullable;

/**
 * This class provides a skeletal implementation of the {@code Iterator} interface for sequences
 * whose next element can always be derived from the previous element. Null elements are not
 * supported, nor is the {@link #remove()} method.
 *
 * <p>Example:
 *
 * {@snippet :
 * Iterator<Integer> powersOfTwo =
 *     new AbstractSequentialIterator<Integer>(1) {