The Flutter CLI doesn't call exit() from many places today:

https://github.com/flutter/flutter/blob/master/packages/flutter_tools/lib/runner.dart#L256
https://github.com/flutter/flutter/blob/master/packages/flutter_tools/lib/src/base/signals.dart#L144

But if it were to start calling exit() from more places, various hard-to-find/racy shutdown inconsistencies could potentially crop up. See the discussion here:

#58474 (comment)

After removing the call to exit() here:

https://github.com/flutter/flutter/blob/master/packages/flutter_tools/lib/src/commands/analyze_continuously.dart#L182

Calls to exit() could be limited using a forbidden_import_test after moving exit() from io.dart to, e.g. exit.dart.

/cc @jamesderlin @jonahwilliams