You can store the resulting WARC file wherever, be it on S3 or under your pillow.
As an archivist, I urge everybody here to not reinvent the wheel, please..
[2] https://en.m.wikipedia.org/wiki/WARC_(file_format)
[3] https://www.iso.org/standard/68004.html
[4] https://www.loc.gov/preservation/digital/formats/fdd/fdd0002...