add weakref to sync engine #1224
| Job | Run time |
|---|---|
| 2m 44s | |
| 4m 42s | |
| 2m 37s | |
| 9m 16s | |
| 4m 44s | |
| 14m 5s | |
| 5m 44s | |
| 14m 6s | |
| 9m 18s | |
| 14m 6s | |
| 5m 37s | |
| 14m 5s | |
| 9m 17s | |
| 14m 5s | |
| 6m 10s | |
| 14m 8s | |
| 9m 18s | |
| 14m 5s | |
| 7m 16s | |
| 14m 4s | |
| 9m 4s | |
| 11m 39s | |
| 4m 48s | |
| 11m 23s | |
| 9m 7s | |
| 11m 28s | |
| 4m 42s | |
| 11m 15s | |
| 9m 6s | |
| 9m 48s | |
| 5m 7s | |
| 9m 51s | |
| 9m 0s | |
| 9m 17s | |
| 5m 15s | |
| 9m 14s | |
| 5h 29m 31s |