naive effect after lost reply and retry: 14
first response: reply lost: caller has an unknown outcome; actual stored total=7
same key: id=1 receipt-total=7 replayed=true error=<nil>
changed input: conflict=true total=7
new key declares another operation: id=2 total=14 error=<nil>
original receipt after later work: found=true total-at-original-commit=7
