message: If our views are equivalent, return nothing.
diff: @@ -629,6 +629,9 @@ impl<I: NodeIdT, C: Context + 'static> HighwayProtocol<I, C> {
  their_next_seq: u64,
  ) -> Vec<HighwayMessage<C>> {
  let state = self.highway.state();
  + if our_next_seq == their_next_seq {
  + return vec![];
  + }
  if our_next_seq < their_next_seq {
  // We're behind. Request missing vertices.
  (our_next_seq..their_next_seq)
  