From the top of my head it doesn't support pagination, since/until can't work for different sort orders.
Discussion
The args could support it, right? I was thinking the algorithm could determine how pages should work, but having something generic would be cool too.
Bloom filters could be a way to probabilistically say “I’ve already seen these ‘pages’ *probably*” … bloom filters could also be drafted in a way that it helps for all req queries and prevents clients from redownloading events across relays.