This was needed so that it could be called from Dart as well as flutter_main/C++.
It turns out flutter_main does not run on the "ui thread", so when Dart was calling
into the updater it would panic due to thinking the updater (which was using a thread local) was not yet initialized.
Also added the log-panics crate on Android so that panics appear in adb logcat.
Eric Seidel