Worth cramming on Swift for WWDC?

Hi folks:

I have, frankly, been too busy to delve much into Swift, although (for the most part) I like what I see so far. However, as I compile my list of things I want to drill down into at the conference, I keep wondering if cramming and trying to learn as much Swift as possible before the conference would be advantageous in any way. Do we expect Apple to do the usual "now everything is another thing" and all of the sudden all of the lecture examples are in Swift? What are your thoughts?

It's better to be over prepared than under prepared.

It's pretty easy code to read. I would just watch an intro video or two. New to me were use of ?, !. Also check out closures.