public static <T> Distinct<T> create() {
    return new Distinct<>();
  }
@Test
  @Category(NeedsRunner.class)
  public void testDistinctEmpty() {
    List<String> strings = Arrays.asList();

    PCollection<String> input = p.apply(Create.of(strings).withCoder(StringUtf8Coder.of()));

    PCollection<String> output = input.apply(Distinct.create());

    PAssert.that(output).empty();
    p.run();
  }