> time mce

volume:		 11881376
chunk_size:	 16000
max_workers:	8

real	0m19.776s
user	0m43.350s
sys	 0m10.321s

> time mce

volume:		 11881376
chunk_size:	 16000
max_workers:	4

real	0m17.615s
user	0m27.495s
sys	 0m4.836s