The part I found non-obvious is how to snapshot the unbounded vectors of immutable registers, which is a requirement for any real system. But I never gave it a

The part I found non-obvious is how to snapshot the unbounded vectors of immutable registers, which is a requirement for any real system. But I never gave it a whole lot of thought either. To snapshot, I either need to find an epoch such that no older epoch could ever have relevant information for the current node, or I need the nodes to agree on a snapshot. Both seem complicated.