Module queue 

The queue storage family: the source header plus a not_before instant that gates when an item becomes due. Absence is a flag bit, not a sentinel instant, so a due-now item stays due-now.

Structs

EncodedQueueRow

EncodedQueueRowBuilder

The write side of the queue family: a buffer whose source header and not_before slot are already reserved, which freezes into an EncodedQueueRow and never into a row of another family.