code: public static void schedule(String threadName) {
      try (LockResource r = new LockResource(sLock)) {
        ScheduledTimer timer = sTimers.get(threadName);
        if (timer == null) {
          throw new RuntimeException("Timer for thread " + threadName + " not found.");
        }
        timer.schedule();
      }
    }
docs: Schedules execution of a heartbeat for the given thread.
  
  @param threadName a name of the thread for which heartbeat is to be executed