select Keyset Paging Source
Create a PagingSource that pages through results using keyset-based pagination. Unlike selectPagingSource, this avoids the O(n) cost of SQL OFFSET on large datasets by using pre-calculated page boundary keys.
Page boundaries are computed once per PagingSource lifecycle. When data changes, the PagingSource is invalidated and a new one is created with fresh boundaries.
Note: PagingSource.jumpingSupported is false for keyset paging — pages must be loaded sequentially from the start or a refresh key.
Parameters
The number of items per page, used to compute stable page boundaries. Should match the PagingConfig.pageSize used with the Pager.
null ignores expiresAt, will not return any row which has expired set and is before expiresAfter. This is normally Clock.System.now.