Bug repro.

unsettling_test.dart

  patrolTest(
    'never settles when an invisible child of IndexedStack is requesting frames',
    ($) async {
      await expectLater(
        () async => $.pumpWidgetAndSettle(
          MaterialApp(
            home: Scaffold(
              body: IndexedStack(
                children: const [
                  Center(child: Text('first child')),
                  Center(child: CircularProgressIndicator())
                ],
              ),
            ),
          ),
        ),
        throwsA(
          isA<AssertionError>().having(
            (err) => err.message,
            'message',
            'pumpAndSettle timed out',
          ),
        ),
      );
    },
  );