docs: @Subscribe
    public void slowHeartBeat(LowLevelHeartBeatEvent e) {
      Description current = null;
      if (tests != null && !tests.isEmpty()) {
        current = tests.peek().getDescription();
      } else {
        current = lastSuite; // may be null.
      }
  
      target.post(new HeartBeatEvent(
          slave,
          current,
          e.lastActivity,
          e.currentTime
      ));
    }