comm.go
func (p *PubSub) getHelloPacket() *RPC {
	var rpc RPC
	for t := range p.myTopics {
		as := &pb.RPC_SubOpts{
			Topicid:   proto.String(t),
			Subscribe: proto.Bool(true),
		}
		rpc.Subscriptions = append(rpc.Subscriptions, as)
	}
	return &rpc
}
func (p *PubSub) getHelloPacket() *RPC {
	var rpc RPC
	for t := range p.myTopics {
		as := &pb.RPC_SubOpts{
			Topicid:   proto.String(t),
			Subscribe: proto.Bool(true),
		}
		rpc.Subscriptions = append(rpc.Subscriptions, as)
	}
	return &rpc
}
// get the initial RPC containing all of our subscriptions to send to new peers