Iterator<String> i2 = Iterators.consumingIterator(list.iterator());

    i1.next();
    assertThrows(ConcurrentModificationException.class, () -> i2.next());
  }

  public void testIndexOf_consumedData() {
    Iterator<String> iterator = Lists.newArrayList("manny", "mo", "jack").iterator();
    assertEquals(1, Iterators.indexOf(iterator, equalTo("mo")));
    assertEquals("jack", iterator.next());