SendTraceScenario already swept framesPerGroup and recorded per-frame
send durations + arrival wall-times, but never correlated them — so it
could verify frame delivery but not the send-side latency a listener
perceives. Record each frame's send wall-clock timestamp and derive the
true send→arrival latency (time-to-first-frame + p50/p99/min/max) per
subscriber. With framesPerGroup > 1 this surfaces the batching window
(~framesPerGroup * cadence) as the latency floor.
Add framesPerGroup=10 and =50 (the production default) sweep entries to
both the prod and local-harness suites so the batching-vs-latency
tradeoff curve is visible in one run.
https://claude.ai/code/session_01PoQupfdoKU3ryQwLwTeXeM
Claude
6b8467bde3