callbacks: supplement single test coverage for CombiningHandler
#2176
| Job | Run time |
|---|---|
| 2m 43s | |
| 20s | |
| 2m 29s | |
| 5m 32s |
CombiningHandler
#2176
| Job | Run time |
|---|---|
| 2m 43s | |
| 20s | |
| 2m 29s | |
| 5m 32s |