@Override
public ImmutableGenericBitmap difference(ImmutableGenericBitmap bitmap)
{
WrappedImmutableRoaringBitmap other = (WrappedImmutableRoaringBitmap) bitmap;
ImmutableRoaringBitmap otherIndex = other.invertedIndex;
return new WrappedImmutableRoaringBitmap(ImmutableRoaringBitmap.andNot(invertedIndex, otherIndex));
}