message: Add peers if they _weren't_ present.
diff: @@ -92,7 +92,7 @@ where
  // set used for filtering out duplicates
  let mut filter_peers: HashSet<I> = self.peers.iter().cloned().collect();
  for peer in other.peers {
  - if !filter_peers.insert(peer.clone()) {
  + if filter_peers.insert(peer.clone()) {
  self.peers.push(peer);
  }
  }
  