claim
abstract suspend fun claim(type: AggregateType, revision: Int, lower: Boolean = false): SnapshotTable
Claims type's table at state revision and returns its record after the claim. The first claim records the table, not yet backfilled, and rebuilding unless revision is 1 (a snapshot written before revisions is of revision 1). A later claim raises a lower revision; it lowers a higher one only when lower says so (a rollback, once no node of the higher revision is left); either change starts a rebuild. Claims are atomic: concurrent claims leave one revision.