[elvinyung]

Yeah, I'm currently getting bitten by various workloads that query by `created_at` instead of a canonical timestamp :) Thanks, I'll take a look!

For the "valid time" primitive I was thinking of implementing something like a hybrid logical clock that CockroachDB has (but with looser guarantees, mostly just need uniqueness and monotonicity). A sequential ID would provide a slightly nicer interface for pagination but has all the problems that I previously mentioned.