使用自定义域名时 `oss2.ObjectIteratorV2` 的 `prefix` 参数无效

[Sun-ZhenXing]

如题，bucket 使用自定义域名，发现 ObjectIteratorV2 不能正常工作。

[Sun-ZhenXing]

提供一个 workaround 方法：同时使用 CDN 加速的 OSS 并且使用一个不加速的桶实例。

实际业务代码：

class OSSManager(RemoteFileManager):
    """阿里云 OSS 文件"""

    def __init__(
        self,
        bucket: oss2.Bucket,
        cname_bucket: oss2.Bucket | None = None,
    ) -> None:
        self._bucket = bucket
        # V2 API 目前有许多 BUG，使用 cname_bucket 过渡
        self._cname_bucket = cname_bucket or bucket

    @staticmethod
    def from_config(d: OSSConfigDict) -> "OSSManager":
        """从配置文件中创建 OSSManager"""
        access_key_id = d["access_key_id"]
        access_key_secret = d["access_key_secret"]
        endpoint = d["endpoint"]
        bucket_name = d["bucket_name"]
        cname = d["cname"] if "cname" in d else None

        auth = oss2.Auth(access_key_id, access_key_secret)
        bucket = oss2.Bucket(
            auth=auth,
            endpoint=endpoint,
            bucket_name=bucket_name,
        )
        cname_bucket = oss2.Bucket(
            auth=auth,
            endpoint=cname or endpoint,
            bucket_name=bucket_name,
            is_cname=cname is not None,
        )
        return OSSManager(bucket, cname_bucket)

    def upload_file(
        self,
        filename: str,
        remote_path: str,
        callback: Callable[[int, int], None],
    ) -> bool:
        """上传文件到 OSS"""
        with open(filename, "rb") as f:
            result = self._bucket.put_object(remote_path, f, progress_callback=callback)
        return result.status in range(200, 300)

    def download_file(
        self,
        remote_path: str,
        filename: str,
        callback: Callable[[int, int], None] | None = None,
    ) -> bool:
        """下载文件"""
        result = self._cname_bucket.get_object_to_file(
            remote_path,
            filename,
            progress_callback=callback,
        )
        return result.status in range(200, 300)