experiment with Midi controls in PairBenchmark to tune variables (will move it into a utility class, so every demo can easier use it in the future)
fix issue with broadphase, not initializing all pairs properly at pair array overflow
The Bullet 3.x B3_PROFILE can be customized using b3SetCustomEnterProfileZoneFunc/b3SetCustomLeaveProfileZoneFunc defined in Bullet3Common/b3Logging,
so you can hook Bullet 3.x up to your profiler of choice.
The Demos3/BasicGpuDemo will show the Bullet 3.x timings inside the Bullet 2.x btQuickprof profiler.