router.go
func (router *Router) Gossip() GossipData {
	return &topologyGossipData{peers: router.Peers, update: router.Peers.names()}
}
func (router *Router) Gossip() GossipData {
	return &topologyGossipData{peers: router.Peers, update: router.Peers.names()}
}
// Gossip yields the current topology as GossipData.