iter: add kani proof for next_unchecked (#280)
#2165
| Job | Run time |
|---|---|
| 6m 57s | |
| 0s | |
| 6m 57s |
kani proof for next_unchecked (#280)
#2165
| Job | Run time |
|---|---|
| 6m 57s | |
| 0s | |
| 6m 57s |