Hello,
it's fine that you have now a Paging Library 3.0 with all the Flow stuff and other new things and so on. But I made my app using the old Paging Library with a BoundaryCallback and I am very happy with that.
I know that the software will always change but at this point, I do not want to integrate Flow into my app because it is an ExperimentalAPI which might be change in the future.
Therefore, I searched for the codelab and the Paging github page which contained the old Paging Library with PagedList.BoundaryCallback and so on.
Can you also upload that old project, please ?