Rails 3: How to identify after_commit action? (create/update/destroy)

I have an observer and I register an after_commit callback.
How can I tell weather it was fired after create or update?
I can tell an item was destroyed by asking item.destroyed?.

I was going to solve it by adding after_create/after_update and do
something like @action = :create inside and check the @action at
after_commit, but it seems that the observer instance is a singleton
and I might just override a value before it gets to the
after_commit. So I solved it in an uglier way, storing the action in
a map based on the item.id on after_create/update and checking its
value on after_commit. Really ugly.

Is there any other way?