enableDiskCache 缓存命中问题

当我开启了硬盘缓存，可是我还加了一个元数据获取失败兜底函数，这个时候只会走硬盘缓存逻辑，兜底函数不生效了

const obj = {
    enableDiskCache: true,
    apiPrefix: item.apiPrefix,
    versionId: item.version,
    hook: {
        beforeAppendAssetNode(passCtx) {
            const { url, setAssetUrl } = passCtx;
            const jsdelivrUrl = url.replace('https://unpkg.com', item.apiPrefix);
            setAssetUrl(jsdelivrUrl);
        },
        onFetchMetaFailed(params) {
            // 返回一份前端预设的元数据对象，用于兜底
            console.log('开始走兜底逻辑', params);
            console.log('备用cdn数据', _DATA);
            return _DATA;
        },
    },
};
try {
    const helMicro = await import('hel-micro');
    SDK = await helMicro.preFetchLib(item.sdk, obj);
} catch (e) {
    console.log('捕获到异常错误', e);
}

Start at the preFetchLib entry point and trace the enableDiskCache path alongside the onFetchMetaFailed hook. Reproduce the case with disk caching enabled and a metadata-fetch failure, then verify that the documented fallback behavior occurs and add or update the relevant test if one exists.