RemSound latency lab - measuring depth-target convergence with the shipped playout code.
Raise under test: 30ms -> 330ms. Expected growth at full depth-bias: ~3ms/s.

--- T3 classic app path: WASAPI lane active, slider drives Mixed ---
  session route after arrival: WasapiLane  (slider writes to: Mixed)
  settled at slider 30ms: buffered=39ms
  t+10s buffered=  19ms
  t+20s buffered=  39ms
  t+30s buffered=  38ms
  t+40s buffered=  29ms
  t+50s buffered=  20ms
  t+60s buffered=  30ms
  RAISE via slider: 39ms -> 30ms in 60s = -0.15ms/s  STALLED (the field bug)
  LOWER via slider: back to 30ms -> buffered=1ms after 3s


=== SUMMARY ===
  T3 classic app path: WASAPI lane active, slider drives Mixed: raise -0.15ms/s [STALLED (the field bug)], lower -> 21ms