Hey @haberman! One of the authors here. We actually do have an arena-esque implementation built on top of pb-jelly internally, as it was needed for Magic Pocket

Hey @haberman! One of the authors here. We actually do have an arena-esque implementation built on top of pb-jelly internally, as it was needed for Magic Pocket. It's built on top of the Blob traits exposed by pb-jelly. It's not yet open-source, but it would be a good candidate to do next! It also definitely has unsafe code to your point. We open sourced the safe implementations that uses more standard types (Bytes/Buffer/Vec) first. There's a decent amount of cleanup needed before we can opensource that as well, as much of it was built years ago, when rust ecosystem was less mature (eg Bytes/Buffer weren't around yet). I like where you're thinking!