$ java CountDownLatchPipeline

main: all 4 workers created, still waiting at the start gate
main: releasing the start gate
worker-0: finished round 1
worker-1: finished round 1
worker-2: finished round 1
worker-3: finished round 1
worker-0: finished round 2
worker-1: finished round 2
worker-2: finished round 2
worker-3: finished round 2
worker-0: finished round 3
worker-1: finished round 3
worker-2: finished round 3
worker-3: finished round 3
done