HarmonyOS如何自定义公共事件，实现appA与appB之间互相通信

参考demo如下：

订阅方：

let subscriber: CommonEventManager.CommonEventSubscriber;
//订阅者信息
let subscribeInfo: CommonEventManager.CommonEventSubscribeInfo = {
  events: ['eventTest']
};

//订阅公共事件回调
function SubscribeCB(err: Base.BusinessError, data: CommonEventManager.CommonEventData) {
  publishNotification();
}

//创建订阅者回调
function createCB(err: Base.BusinessError, commonEventSubscriber: CommonEventManager.CommonEventSubscriber) {
  if (!err) {
    hilog.info(0xFF00, LOG_TAG, 'createSubscriber');
    subscriber = commonEventSubscriber;
    //订阅公共事件
    CommonEventManager.subscribe(subscriber, SubscribeCB);
  } else {
    hilog.error(0xFF00, LOG_TAG, `createSubscriber failed, code is ${err.code}, message is ${err.message}`);
  }
}

发布方：

// 公共事件相关信息
let options: CommonEventManager.CommonEventPublishData = {
  bundleName: 'com.example.mysubscriber', //表示订阅者包名称，只有包名为bundleName的订阅者才能收到该公共事件。
};
CommonEventManager.publish('eventTest', options, (err: Base.BusinessError) => {
  if (err) {
    //todo 模板字符串
    hilog.error(0xFF00, LOG_TAG, `PublishCallBack err = ${JSON.stringify(err)}`);
  } else {
    hilog.info(0xFF00, LOG_TAG, 'commonEvent Publish success');
  }
});