$ time perl script.pl
Called: 0
Called: 1
:
Called: 99998
Called: 99999

real    12m23.351s
user    10m50.800s
sys     0m23.580s

##</code><code>##

Called: 367
Called: 368
Thread creation failed: pthread_create returned 11 at script line 4.
Can't call method "detach" on an undefined value at script line 5.