fn subscribeKeyOf

data OrderEvent {
  userId: u64
  seq: i64
}

topic OrderEvents: OrderEvent sharded by .userId

cluster demo {
  role store { journal }
}

fn main() -> () | TopicError io, db {
  OrderEvents.publish(OrderEvent{ userId: 1, seq: 10 })?
  OrderEvents.publish(OrderEvent{ userId: 2, seq: 20 })?
  for await e in OrderEvents.subscribeKey(2 as u64, from: .Earliest) {
    print("{e.seq}")
    break
  }
}

20