message: Address Bart's review comment.
diff: @@ -143,7 +143,7 @@ impl<C: Context> RoundSuccessMeter<C> {
  pub fn next_era(&self, era_start_timestamp: Timestamp) -> Self {
  let current_round_id = round_id(era_start_timestamp, self.current_round_exp).millis();
  Self {
  - rounds: Default::default(),
  + rounds: self.rounds.clone(),
  current_round_id,
  proposals: Default::default(),
  min_round_exp: self.min_round_exp,
  