set.remove("b");
    set.addAll(Lists.newArrayList("X", "Y", "Z"));
    assertThat(tail).containsExactly("c", "X", "Y", "Z").inOrder();
  }

  public void testSkip_structurallyModifiedSkipSomeList() throws Exception {
    List<String> list = Lists.newArrayList("a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(list).skip(1);
    list.subList(1, 3).clear();