code: protected long calcScoreInRegionKeysSet(long expireSeconds) {
  		long currentTime = System.currentTimeMillis() / 1000;
  		long score = currentTime + expireSeconds - this.baseScoreInRegionKeysSet;
  		return score;
  	}
docs: 避免关联key集合越积越多，按插入的先后顺序计算score便于后续定期删除。<br>
  Score 即为 实际过期时间的时间戳
  
  @return