Back Log Statistics
Statistic adapter that exposes a BackLogQueue's queue-level statistics (number-in-queue, time-in-queue) and the policy's amount-backlogged statistics through BackLogStatisticsIfc.
The runtime casts on numInQ / timeInQ / amtBackLoggedResponse are safe because BackLogQueue always constructs the concrete KSL response types.
See sc.inventorylayer.BackLogStatistics