Future.isDone and getDone doesn't imply the Future was successful
and it may have been cancelled or failed.
In case where we handle failure, we should also handle cancellation
to avoid CancellationException to bubble up unchecked.
In demo app code where we use isDone for field initialization, we
want to crash in the failure case (usually security exception where
the connection is disallowed), but we want to gracefully handle
cancellation. Cancellation of these variables usually happens in
Activity.onDestroy/onStop, but methods may be called after this point.
#minor-release
PiperOrigin-RevId: 572178018
fe7c62afe0