The example finishes history() before connecting stream_ticks(). An update between those two steps can be missing even if later duplicates are removed. I would connect and buffer the stream first, backfill through a recorded watermark, then merge the buffered events with an explicit overlap rule. A fixture with a tick arriving during the history request would test that handover directly.
Arnold Holm
Challenge Pre-Check: know before you risk. Your rules, tested against prop limits. Historical simulation, not a forecast.
The example finishes history() before connecting stream_ticks(). An update between those two steps can be missing even if later duplicates are removed. I would connect and buffer the stream first, backfill through a recorded watermark, then merge the buffered events with an explicit overlap rule. A fixture with a tick arriving during the history request would test that handover directly.