public static <T> Values<T> of(Iterable<T> elems) {
    return new Values<>(elems, Optional.absent(), Optional.absent(), false);
  }
@Test
  public void testSourceIsSerializableWithUnserializableElements() throws Exception {
    List<UnserializableRecord> elements =
        ImmutableList.of(
            new UnserializableRecord("foo"),
            new UnserializableRecord("bar"),
            new UnserializableRecord("baz"));
    CreateSource<UnserializableRecord> source =
        CreateSource.fromIterable(elements, new UnserializableRecord.UnserializableRecordCoder());
    SerializableUtils.ensureSerializable(source);
  }