at
fun at(ledger: EntitlementLedger, parent: GroupId, roster: Set<ReplicaId>, demanding: Set<AttachmentId>, config: HeddleConfig): BoundMetrics
Derive the bound metrics at parent from the merged ledger, the live roster (every peer that can steer entitlement here — including self and currently unreachable peers, since a partitioned peer is exactly the divergence source the bound must count), the set of demanding child edges (those advertising live demand), and the config caps. Pure — a function of the arguments, computed identically on every peer that has merged the same state.