startBackgroundWarmup
Spawn the warmup threads described above: preload, and the gate that awaits both halves. Called once from CommonClass.init. Both run below-normal priority to yield to the game's own startup work.
Spawn the warmup threads described above: preload, and the gate that awaits both halves. Called once from CommonClass.init. Both run below-normal priority to yield to the game's own startup work.