hubMesh
suspend fun hubMesh(selfId: PeerId, connections: List<Connection>, dispatcher: CoroutineContext, random: Random = Random.Default, policy: DeliveryPolicy = DeliveryPolicy.Reliable, admission: LinkAdmission = LinkAdmission.AcceptAll): Mesh
Build a hub-mesh Seam — the start-empty-and-grow topology (a host admitting joiners).
A hub legitimately sits at an empty link set: it is constructed with connections = emptyList() and grows via Mesh.addLink as joiners dial in, and it may drain back to empty between joiners without its session ending. A hub therefore never self-torns on drain — it terminates only via Seam.close. This is exactly today's meshSeam behaviour, named explicitly.
Contrast peerMesh, which latches SeamState.Torn when its last link drops. All parameters behave exactly as documented on meshSeam.