This might obviate the need for Flutter's --trace-systrace flag such that timeline events would automagically go to Android system tracing when Android tooling is attached, and would otherwise be sent to Flutter/Dart's tooling otherwise.

However, I'm not sure whether the flag would need to be checked for every event, or only checked once at VM/tracing startup.

https://developer.android.com/ndk/reference/group/tracing#group___tracing_1gad839953d2c6d4189ec80f7b028f7f778