HarmonyOS 走文件夹获取的图片怎么查看他的图片大小（比如10M，50KB这种）

参考下这个demo，用fs读取文件大小，按1000换算可以拿到文件的大小：

import camera from '@ohos.multimedia.camera';
import common from '@ohos.app.ability.common';
import { BusinessError } from '@ohos.base';
import fileuri from '@ohos.file.fileuri';
import fs from '@ohos.file.fs';
import picker from '@ohos.file.picker';
import photoAccessHelper from '@ohos.file.photoAccessHelper';
import buffer from '@ohos.buffer';

async function get() {
  const photoSelectOptions = new photoAccessHelper.PhotoSelectOptions();
  photoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.IMAGE_TYPE; // 过滤选择媒体文件类型为IMAGE
  photoSelectOptions.maxSelectNumber = 5; // 选择媒体文件的最大数目
  let uris: Array<string> = [];
  const photoViewPicker = new photoAccessHelper.PhotoViewPicker();
  photoViewPicker.select(photoSelectOptions).then((photoSelectResult: photoAccessHelper.PhotoSelectResult) => {
    uris = photoSelectResult.photoUris;
    console.info('photoViewPicker.select to file succeed and uris are:' + uris);
    let file = fs.openSync(uris[0], fs.OpenMode.READ_WRITE);
    fs.stat(file.fd).then((stat: fs.Stat) => {
      console.info("lstat succeed, the size of file is " + stat.size);
    }).catch((err: BusinessError) => {
      console.error("lstat failed with error message: " + err.message + ", error code: " + err.code);
    });
  }).catch((err: BusinessError) => {
    console.error(`Invoke photoViewPicker.select failed, code is ${err.code}, message is ${err.message}`);
  })
}

@Entry
@Component
export struct Index {
  build() {
    Column() {
      Button('选择并保存').onClick(() => {
        get()
      })
    }
  }
}