Test that multipe workers can be spawned simultaneously. Should print "DONE" when done. SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized SUCCESS: Worker context initialized DONE