Flaky segfault error

[byeonggiljun]

AsyncCallback.lf failed in this CI run. The error report was like

Reported issues:
Exit code: 139
This exit code typically indicates a segfault. In this case, the execution output is likely missing or incomplete.

However, I couldn't reproduce it on my local computer, and the PR lf-lang/reactor-c#445 only has changes related to the federated execution. Thus, it shouldn't be the problem caused by the PR.