code: func (sn *SimNode) SubscribeEvents(ch chan *p2p.PeerEvent) event.Subscription {
  	srv := sn.Server()
  	if srv == nil {
  		panic("node not running")
  	}
  	return srv.SubscribeEvents(ch)
  }
docs: // SubscribeEvents subscribes the given channel to peer events from the
  // underlying p2p.Server