code: func (packet *packetMock) Respond(msg *proto.GossipMessage) {
  	sMsg, _ := msg.NoopSign()
  	packet.src.socket <- &packetMock{
  		src: packet.dst,
  		dst: packet.src,
  		msg: sMsg,
  	}
  }
docs: // Respond sends a GossipMessage to the origin from which this ReceivedMessage was sent from