routes.go
func (r *routes) BroadcastAll(name PeerName) []PeerName {
	return r.lookupOrCalculate(name, &r.broadcastAll, false)
}
func (r *routes) BroadcastAll(name PeerName) []PeerName {
	return r.lookupOrCalculate(name, &r.broadcastAll, false)
}
// BroadcastAll returns the set of peer names that should be notified
// when we receive a broadcast message originating from the named peer
// based on all connections.