message: Make should_activate immutable.
diff: @@ -260,24 +260,26 @@ where
  let our_id = self.public_signing_key;
  let era_rounds_len = params.min_round_len() * params.end_height();
  let min_end_time = start_time + self.highway_config().era_duration.max(era_rounds_len);
  - let mut should_activate = false;
  - if self.node_start_time >= start_time {
  + let should_activate = if self.node_start_time >= start_time {
  info!(
  era = era_id.0,
  %self.node_start_time, "not voting; node was not started before the era began",
  );
  + false
  } else if min_end_time < timestamp {
  info!(
  era = era_id.0,
  %min_end_time,
  "not voting; era started too long ago",
  );
  + false
  } else if !validators.iter().any(|v| *v.id() == our_id) {
  info!(era = era_id.0, %our_id, "not voting; not a validator");
  + false
  } else {
  info!(era = era_id.0, "start voting");
  - should_activate = true;
  - }
  + true
  + };
  let mut highway = HighwayProtocol::<I, HighwayContext>::new(
  instance_id(&self.chainspec, state_root_hash, start_height),
  