我希望调用我的云函数接口后，立即返回，并且异步去做耗时操作。现在是接口有返回，但是云函数会判断超时，我的耗时操作并没有完成

router.post('/updateItem', async function (ctx, next) {
    const { ENV, OPENID, APPID } = cloud.getWXContext()


    const {
        collection, _id, itemid
    } = JSON.parse(ctx.req.body.toString('utf-8'))


    const db = cloud.database()
    let { data: orderList } = await db
        .collection('order')
        .doc(_id).get();


    if (orderList) {


        let item = { ...orderList.items[itemid] }
        item.collection = collection
        orderList.items.splice(item.id, 1, item)


        await db
            .collection('order')
            .doc(_id).update({
                data: {
                    items: orderList.items
                }
            })

        // 耗时操作
        generateZip(orderList, item)


        ctx.body = {
            code: 0,
            data: ""
        }
    }
    else {
        ctx.body = {
            code: -1,
            msg: "找不到订单"
        }
    }
})

async function generateZip(order, boughtItem) {
  
}

日志报错

ERROR RequestId:caf47d0e-2a00-11eb-9171-5254002665ac Result:{"errorCode":-1,"errorMessage":"Async invoking task timed out after 5 seconds"} 

END RequestId: caf47d0e-2a00-11eb-9171-5254002665ac

Report RequestId: caf47d0e-2a00-11eb-9171-5254002665ac Duration:5000ms Memory:256MB MemUsage:72.132812MB