code: private void setAcquired(HLock lock, Map<String, String> canBeEarlier) {
      // start the heartbeat
      Future<Void> heartbeat = scheduler.schedule(new Heartbeat(lock), lockTtl / 2, TimeUnit.MILLISECONDS);
  
      ((HLockImpl) lock).setHeartbeat(heartbeat);
  
      ((HLockImpl) lock).setAcquired(true);
  
      if (logger.isDebugEnabled()) {
        logLock(lock, canBeEarlier.keySet());
      }
  
    }
docs: Start the heartbeat thread before we return
  
  @param lock