@Test
public void testLazyFlatMapKeepSize() {

  List<Integer> eval = mlazy(asList(1))
          .flatMap(new Function<Integer, Iterator<Integer>>() {
            @Override
            public Iterator<Integer> apply(Integer integer) {
              return Option.<Integer>some(2).iterator();
            }
          })
          .eval();
  assertArrayEquals(new Integer[]{2}, eval.toArray(new Integer[0]));
}