@SuppressWarnings("unchecked") // it's definitely equal to a K
      K k = (K) key;
      List<V> result = new ArrayList<>();
      Iterator<V> itr = collection.iterator();
      while (itr.hasNext()) {
        V v = itr.next();
        if (satisfies(k, v)) {
          itr.remove();
          result.add(v);
        }
      }
      if (result.isEmpty()) {
        return null;

      @SuppressWarnings("unchecked") // it's definitely equal to a K
      K k = (K) key;
      List<V> result = new ArrayList<>();
      Iterator<V> itr = collection.iterator();
      while (itr.hasNext()) {
        V v = itr.next();
        if (satisfies(k, v)) {
          itr.remove();
          result.add(v);
        }
      }
      if (result.isEmpty()) {
        return null;

   */
  int adjustAfterRemove(int indexBeforeRemove, @SuppressWarnings("unused") int indexRemoved) {
    return indexBeforeRemove - 1;
  }

  private abstract class Itr<T extends @Nullable Object> implements Iterator<T> {
    int expectedMetadata = metadata;
    int currentIndex = firstEntryIndex();
    int indexToRemove = -1;

    @Override
    public boolean hasNext() {

    } else {
      return new Itr<E>(this, index);
    }
  }

  /** A singleton implementation of iterator() for the empty ImmutableList. */
  // TODO(b/345814817): Move this to RegularImmutableList?
  @SuppressWarnings("ClassInitializationDeadlock")
  private static final UnmodifiableListIterator<Object> EMPTY_ITR =
      new Itr<Object>(RegularImmutableList.EMPTY, 0);

  @Override
  public Iterator<E> iterator() {
    return new Itr(toArray());
  }

  /** Snapshot iterator that works off copy of underlying q array. */
  private class Itr implements Iterator<E> {
    final Object[] array; // Array of all elements
    int cursor; // index of next element to return;
    int lastRet; // index of last element, or -1 if no such

    Itr(Object[] array) {
      lastRet = -1;

  @Override
  public Iterator<E> iterator() {
    Monitor monitor = this.monitor;
    monitor.enter();
    try {
      return new Itr();
    } finally {
      monitor.leave();
    }
  }

  /** Iterator for MonitorBasedArrayBlockingQueue */
  private class Itr implements Iterator<E> {
    /** Index of element to be returned by next, or a negative number if no such. */
    private int nextIndex;

    /**

   */
  int adjustAfterRemove(int indexBeforeRemove, @SuppressWarnings("unused") int indexRemoved) {
    return indexBeforeRemove - 1;
  }

  private abstract class Itr<T extends @Nullable Object> implements Iterator<T> {
    int expectedMetadata = metadata;
    int currentIndex = firstEntryIndex();
    int indexToRemove = -1;

    @Override
    public boolean hasNext() {

      collection.clear();
      totalSize -= count;
    }
  }

  private abstract class Itr<T extends @Nullable Object> implements Iterator<T> {
    final Iterator<Entry<K, Collection<V>>> keyIterator;
    @Nullable K key;
    @Nullable Collection<V> collection;
    Iterator<V> valueIterator;

    Itr() {
      keyIterator = map.entrySet().iterator();
      key = null;
      collection = null;