Shows how to use the ListView.builder to incrementally load data when the last item in the list view scrolls into view

IMPORTANT this is an outdated sample that was built a while before Flutter hit 1.0. I recommend using the following package that I've created

https://pub.dev/packages/incrementally_loading_listview

The GitHub repository for the package can be found at https://github.com/MaikuB/incrementally_loading_listview and has an example on how it can be used