It only checks if [startingIndex] is greater than [catalogLength] in the existing implementation. It doesn't check the index of an item in a page. So it may generate more items than the number specified by [catalogLength]. i.e if [catalogLength] is 113, the existing implementation will still generate 120 items. This PR solves the issue by adding the check for the indices of items in a page.
This PR adds a Flutter sample app that shows an implementation of the "infinite list" UX pattern. That is, a list is shown to the user as if it was continuous although it is internally paginated. This is a common feature of mobile apps, from shopping catalogs through search engines to social media clients.
