When with was proposed, one of the possible additions was transactional with, which is pretty much what you proposed. The problem is that with/for are compile time constructs, Multi works at runtime which is quite more flexible.
Regarding the “after” callback, we should add a new operation to the multi that receives the result of the Repo operation {:ok, ...} or {:error, ...} and return either {:ok, map} | {:error, map}. Can you please open up an issue? I would like to hear yours and @michalmuskala’s feedback.
