message: [consensus] short circuit if already voted
  Closes:
  Approved by: davidiw
diff: @@ -630,6 +630,13 @@ impl<T: Payload> RoundManager<T> {
  block.round(),
  );
  + // Short circuit if already voted.
  + ensure!(
  + self.pacemaker.vote_sent().is_none(),
  + "Already vote on this round {}",
  + self.pacemaker.current_round()
  + );
  +
  let parent_block = self
  .block_store
  .get_block(executed_block.parent_id())
  