HarmonyOS RawFile的文件如何计算md5，如何copy资源到files目录？

可先将rawfile下的文件拷贝到应用的沙箱路径，然后通过Hash.hash的接口计算文件的hash值，参考代码如下：

Text('拷贝文件到沙箱').fontSize('30vp').onClick(() => {
  getContext(this).resourceManager.getRawFileContent('img/1-beer.png', (_err, value) => {
    let myBuffer:ArrayBufferLike = value.buffer
    let context = getContext(this);
    //沙箱路径
    let filePath = context.filesDir + "/67.png";
    console.log("testTag-filePath:" + filePath);
    let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
    let writeLen = fs.writeSync(file.fd, myBuffer);
    console.info("testTag-write data to file succeed and size is:" + writeLen);
    fs.closeSync(file);

    Hash.hash(filePath, "sha256").then((str: string) => {
      console.info("calculate file hash succeed:" + str);
    }).catch((err: BusinessError) => {
      console.error("calculate file hash failed with error message: " + err.message + ", error code: " + err.code);
    });
  });
})