router.go
func (router *Router) sendAllGossipDown(conn Connection) {
	for channel := range router.gossipChannelSet() {
		if gossip := channel.gossiper.Gossip(); gossip != nil {
			channel.SendDown(conn, gossip)
		}
	}
}
func (router *Router) sendAllGossipDown(conn Connection) {
	for channel := range router.gossipChannelSet() {
		if gossip := channel.gossiper.Gossip(); gossip != nil {
			channel.SendDown(conn, gossip)
		}
	}
}
// Relay all pending gossip data for each channel via conn.