checkState(Objects.equals(value, get(getKey())), "entry no longer in map");
      updateInverseMap(getKey(), true, oldValue, value);
      return oldValue;
    }
  }

  Iterator<Entry<K, V>> entrySetIterator() {
    Iterator<Entry<K, V>> iterator = delegate.entrySet().iterator();
    return new Iterator<Entry<K, V>>() {
      @Nullable Entry<K, V> entry;

      @Override
      public boolean hasNext() {

    }

    @Override
    public void clear() {
      CompactHashMap.this.clear();
    }

    @Override
    public Iterator<Entry<K, V>> iterator() {
      return entrySetIterator();
    }

    @Override
    public boolean contains(@Nullable Object o) {
      Map<K, V> delegate = delegateOrNull();
      if (delegate != null) {
        return delegate.entrySet().contains(o);