/** Constructor for use by subclasses. */
    public StandardDescendingMap() {}

    @Override
    NavigableMap<K, V> forward() {
      return ForwardingNavigableMap.this;
    }

    @Override
    public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
      forward().replaceAll(function);
    }

    @Override
    protected Iterator<Entry<K, V>> entryIterator() {

    @Override
    NavigableMap<K, V> forward() {
      return ForwardingNavigableMap.this;
    }

    @Override
    protected Iterator<Entry<K, V>> entryIterator() {
      return new Iterator<Entry<K, V>>() {
        @CheckForNull private Entry<K, V> toRemove = null;
        @CheckForNull private Entry<K, V> nextOrNull = forward().lastEntry();

        @Override