>>> orbital ~/devtools/libphutil $ php -f hfuture.php
sleep 5
sleep 5
sleep 5
sleep 5
sleep 1
sleep 1
sleep 1
sleep 1
sleep 1
sleep 1
[T = 0.0] Starting 10 tasks.
wait 3
[T = 9.0] Completed a task.
wait 3
[T = 13.0] Completed a task.
wait 3
[T = 17.0] Completed a task.
wait 3
[T = 21.0] Completed a task.
wait 3
[T = 25.0] Completed a task.
[T = 25.0] Completed a task.
[T = 25.0] Completed a task.
[T = 25.0] Completed a task.
[T = 25.0] Completed a task.
[T = 26.0] Completed a task.
[T = 26.0] Done.