BGP models are huge, we need some kind of wildcarded subtree writer, that works for whole subtree.

1) we can either move checking handledTypes to writers (getHandledTypes, isAffected, writer.getHandedTypes, ...)
but then precondition check in flatWriterRegistry might be slower (we need to check if we have all writers
in order to avoid unnecessary reverts).

2) alternative is to compute all child nodes during initialization (might introduce some footprint penalty).