private int sumForChildren(@NotNull ToIntFunction<? super ChangesBrowserNode<?>> counter) {
    int sum = 0;
    for (int i = 0; i < getChildCount(); i++) {
      ChangesBrowserNode<?> child = (ChangesBrowserNode<?>)getChildAt(i);
      sum += counter.applyAsInt(child);
    }
    return sum;
  }
private int sumForChildren(@NotNull ToIntFunction<? super ChangesBrowserNode<?>> counter)