如何在 Firebase Cloud Functions 中确认 PubSub 消息？

我想知道确认 PubSub 消息（来自推送订阅者）的正确方法是什么，这是一个 Firebase 云函数。这是通过返回承诺来完成的吗？

import * as functions from 'firebase-functions'
import * as admin from 'firebase-admin'

export const listener = functions.pubsub.topic('new_members').onPublish(async (message:any) => {

let data = {
  name: 'Los Angeles',
  state: 'CA',
  country: 'USA'
};

// Will a PubSub message be acknowledged just by retuning a promise?
return await db.collection('cities').doc('LA').set(data);
}

谢谢你的帮助。