gauge

id's stored virtual-time Gauge, or null when the edge carries none — either it has never been seated, or this view is simply missing the patch that seated it. The two are indistinguishable here on purpose: absence is the seat-bump predicate (see Gauge), and it is a local read, so a peer that has not seen the seat may re-seat from its own front. That is safe precisely because its bump folds its own observed issuance.