public static <T> ListCoder<T> of(Coder<T> elemCoder) {
    return new ListCoder<>(elemCoder);
  }
@Test
  public void testListWithNullsAndSerializableCoder() throws Exception {
    List<Integer> list = Arrays.asList(1, 2, 3, null, 4);
    Coder<List<Integer>> coder = ListCoder.of(SerializableCoder.of(Integer.class));
    CoderProperties.coderDecodeEncodeEqual(coder, list);
  }