HarmonyOS 如何监听修改系统时间的变化？

参考demo：

let subscriber:CommonEventManager.CommonEventSubscriber; //用于保存创建成功的订阅者对象，后续使用其完成订阅及退订的动作

//订阅者信息
let subscribeInfo:CommonEventManager.CommonEventSubscribeInfo = {
  events: ['usual.event.TIME_TICK', 'usual.event.TIME_CHANGED']
};

//订阅公共事件回调
function SubscribeCB(err:Base.BusinessError, data:CommonEventManager.CommonEventData) {
  if (err) {
    console.error(`subscribe failed, code is ${err.code}, message is ${err.message}`);
  } else {
    console.info("subscribe XXXXXXXXXXXXXXXXXXXXXXXXX");
  }
}

//创建订阅者回调
function createCB(err:Base.BusinessError, commonEventSubscriber:CommonEventManager.CommonEventSubscriber) {
  if(!err) {
    console.info("createSubscriber");
    subscriber = commonEventSubscriber;
    //订阅公共事件
    try {
      CommonEventManager.subscribe(subscriber, SubscribeCB);
    } catch (error) {
      let err:Base.BusinessError = error as Base.BusinessError;
      console.error(`subscribe failed, code is ${err.code}, message is ${err.message}`);
    }
  } else {
    console.error(`createSubscriber failed, code is ${err.code}, message is ${err.message}`);
  }
}

//创建订阅者
try {
  CommonEventManager.createSubscriber(subscribeInfo, createCB);
} catch (error) {
  let err:Base.BusinessError = error as Base.BusinessError;
  console.error(`createSubscriber failed, code is ${err.code}, message is ${err.message}`);
}