I have an interesting question about event receivers.
I have long running ItemAdded event. But as soon as item is saved, another or the same user can edit it, even before async event finished. The item also has attached ItemUpdated event. Does Updated event fire after Added event is finished, or can they run simultaneusly? Because it could cause conflicts, if second event runs before first finishes. In that case I have to implement extra safeguards in ItemUpdating.
I think that would be a larger problem, if asynchronous events can run simultaneously on the same item. Because even editing one item twice in short time could lead to conflicts if both events fire at the same time.