HarmonyOS使用ArkTS提供的fs读文件，其中ReadTextOptions报错如下：

/** 
 * 以文本方式读取文件 
 * @param path 文件路径 
 * @returns 文件内容 
 */ 
public static readFileStr(path: string): string { 
  let str = ""; 
  if (this.checkFileExist(path)) { 
    let readTextOptions: ReadTextOptions = { 
      offset: 0, 
      length: 0, 
      encoding: 'utf-8' 
    }; 
    let stat = fs.statSync(path); 
    readTextOptions.length = stat.size; 
    str = fs.readTextSync(path, readTextOptions); 
    console.info("FileUtils readText succeed:\n" + str); 
  } 
return str;  
}