如何实现短时任务的申请和回调?

import { backgroundTaskManager } from '@kit.BackgroundTasksKit';
import { BusinessError } from '@kit.BasicServicesKit';
let id: number;         // 任务ID
let delayTime: number;  // 剩余时间

// 申请短时任务
function requestSuspendDelay() {
  let myReason = 'test requestSuspendDelay';    let delayInfo = backgroundTaskManager.requestSuspendDelay(myReason, () => {
        console.info('suspend delay task will timeout');
    backgroundTaskManager.cancelSuspendDelay(id);
  })
  id = delayInfo.requestId;
  delayTime = delayInfo.actualDelayTime;
}