use_file: replace mutex with nanosleep-based loop
#19
| Job | Run time |
|---|---|
| 15s | |
| 2m 11s | |
| 24s | |
| 2m 50s |
nanosleep-based loop
#19
| Job | Run time |
|---|---|
| 15s | |
| 2m 11s | |
| 24s | |
| 2m 50s |