perf: hipo2npz memory efficiency
#3596
| Job | Run time |
|---|---|
| 4m 11s | |
| 5s | |
| 4m 7s | |
| 4s | |
| 20m 50s | |
| 20m 47s | |
| 9m 1s | |
| 4m 44s | |
| 7m 19s | |
| 2m 8s | |
| 8m 33s | |
| 8m 32s | |
| 8m 32s | |
| 9m 33s | |
| 9m 15s | |
| 8m 33s | |
| 0s | |
| 9m 26s | |
| 6m 29s | |
| -1s | |
| 1m 3s | |
| 0s | |
| 0s | |
| 2h 23m 11s |