public void testClear() {
    getMap().clear();
    assertTrue("After clear(), a map should be empty.", getMap().isEmpty());
    assertEquals(0, getMap().size());
    assertFalse(getMap().entrySet().iterator().hasNext());
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithEntrySetIteration() {
    assertThrows(

  private var constructed = false

  private var peekedHeader: DerHeader? = null

  private val bytesLeft: Long
    get() = if (limit == -1L) -1L else (limit - byteCount)

  fun hasNext(): Boolean = peekHeader() != null

  /**
   * Returns the next header to process unless this scope is exhausted.
   *
   * This returns null if:
   *
   *  * The stream is exhausted.

    while (keyValues.hasNext() && newValues.hasNext()) {
      keyValues.next();
      keyValues.set(newValues.next());
    }

    // Remove remaining old values, if any.
    while (keyValues.hasNext()) {
      keyValues.next();
      keyValues.remove();
    }

    // Add remaining new values, if any.
    while (newValues.hasNext()) {
      keyValues.add(newValues.next());
    }

   * <i>may</i> prevent removal of the most recent element via {@link #remove()}.
   *
   * @throws NoSuchElementException if the iteration has no more elements according to {@link
   *     #hasNext()}
   */
  @ParametricNullness
  E peek();

  /**
   * {@inheritDoc}
   *
   * <p>The objects returned by consecutive calls to {@link #peek()} then {@link #next()} are

    abstract T output(@ParametricNullness K key, @ParametricNullness V value);

    @Override
    public boolean hasNext() {
      return keyIterator.hasNext() || valueIterator.hasNext();
    }

    @Override
    @ParametricNullness
    public T next() {
      if (!valueIterator.hasNext()) {
        Entry<K, Collection<V>> mapEntry = keyIterator.next();
        key = mapEntry.getKey();

      Iterator<Map.Entry<E, Integer>> backingEntries = backingMap.entrySet().iterator();
      return new UnmodifiableIterator<Multiset.Entry<E>>() {
        @Override
        public boolean hasNext() {
          return backingEntries.hasNext();
        }

        @Override
        public Multiset.Entry<E> next() {
          Map.Entry<E, Integer> mapEntry = backingEntries.next();

      @Nullable K currentKey = null;
      Iterator<V> valueItr = emptyIterator();

      @Override
      public boolean hasNext() {
        return valueItr.hasNext() || asMapItr.hasNext();
      }

      @Override
      public Entry<K, V> next() {
        if (!valueItr.hasNext()) {
          Entry<K, ? extends ImmutableCollection<V>> entry = asMapItr.next();
          currentKey = entry.getKey();

    final UnmodifiableIterator<Entry<K, V>> entryIterator = entrySet().iterator();
    return new UnmodifiableIterator<K>() {
      @Override
      public boolean hasNext() {
        return entryIterator.hasNext();
      }

      @Override
      public K next() {
        return entryIterator.next().getKey();
      }
    };
  }

  public void testClear() {
    getMap().clear();
    assertTrue("After clear(), a map should be empty.", getMap().isEmpty());
    assertEquals(0, getMap().size());
    assertFalse(getMap().entrySet().iterator().hasNext());
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithEntrySetIteration() {
    assertThrows(

      @Nullable K currentKey = null;
      Iterator<V> valueItr = emptyIterator();

      @Override
      public boolean hasNext() {
        return valueItr.hasNext() || asMapItr.hasNext();
      }

      @Override
      public Entry<K, V> next() {
        if (!valueItr.hasNext()) {
          Entry<K, ? extends ImmutableCollection<V>> entry = asMapItr.next();
          currentKey = entry.getKey();