How can I use r2/s3?

[cinjon]

I saw the extensive guide for datasets, https://docs.nvidia.com/deeplearning/nemo/user-guide/docs/en/main/asr/datasets.html, and I see that it's using WebDataset, which means it should be possible to use S3 or R2. How do I do this using the NeMo manifest approach? I'm specifically looking for R2 assistance but that's usually compatible with S3 as long as I can set the endpoint url. Thanks.