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?