ScrollView with lazy loading

Hi,
I need to improve the user experience of my app, so i want to create a lazy loading for my ScrolllView. Searching on the net I found this solution for ios that would be a good solution also for me (http://stackoverflow.com/questions/6012237/monotouch-lazyload-uiscrollview) but this first problem is how i call the "scrolled" method on Xmarin.Forms ScrollView?

The next thing is that I want to always center an item when the scroll animation is over. There is some ready example for the ScrollView?

Thanks a lot.