anchor.diff:  void main() {
     group('Randomize Stream', () {
       test('Single batch', () async {
  +      final input = List.generate(10, (i) => i);
         final Stream<int> randomizedStream = randomizeStream(
  -        Stream.fromIterable(List.generate(10, (i) => i)),
  +        Stream.fromIterable(input),
           duration: Duration(milliseconds: 100),
           random: Random(123),
         );
  -      expect(await randomizedStream.toList(), [4, 3, 2, 8, 7, 5, 9, 1, 0, 6]);
  +      final result = await randomizedStream.toList();
  +      expect(input.every(result.contains), isTrue);
  +      expect(result, isNot(input)); // checks that items are randomized
       });
   
       test('Two batches', () async {
  
positive.code:       List.generate(8, (i) => i).forEach(controller.add);
        List.generate(8, (i) => i + 10).forEach(controller.add);
        controller.close();
        // 0-3, 4-7, 10-13, 14-17 in separate batches
        expect(await valuesFuture,
            [3, 1, 0, 2, 4, 5, 6, 7, 11, 13, 12, 10, 16, 14, 17, 15]);
      });
    });
  
  
negative.code:       await Future.delayed(Duration(milliseconds: 200));
        List.generate(8, (i) => i + 10).forEach(controller.add);
        controller.close();
        final result = await valuesFuture;
        final input = [0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17];
        expect(input.every(result.contains), isTrue);
        expect(result, isNot(input)); // checks that items are randomized
      });
  
      test('Small slices', () async {
  