docs: function rmdir(p, reserve) {
    if (!isDirectory(p)) return Promise.resolve();
    return fsReaddir(p).then(files => {
      const promises = files.map(item => {
        const filepath = path.join(p, item);
        if (isDirectory(filepath)) return rmdir(filepath, false);
        return fsUnlink(filepath);
      });
      return Promise.all(promises).then(() => {
        if (!reserve) return fsRmdir(p);
      });
    });
  }