Did you know you can now upgrade a rented movie to a purchase for a discount?

I didn't know this, and I can't find any mention of it anywhere in the iTunes documentation. In fact, I see many threads requesting this featured dating back many years. It seems that Apple have quietly added a feature that allows you to turn a movie rental into a purchase, whilst you are watching the rental. I just rented Avengers: Age Of Ultron, and in iTunes in the playback bar at the top was a $19.99 price button. Normally, to buy the movie it is 24.99 and rental is 5.99. So it seems that you can, whilst the rental is still active, upgrade it to a purchase!