public static <InputT> KeyByBuilder<InputT> of(PCollection<InputT> input) {
    return named(null).of(input);
  }
@Test
  public void testBuild_ImplicitName() {
    final PCollection<String> dataset = TestUtils.createMockDataset(TypeDescriptors.strings());
    final PCollection<KV<String, Long>> counted = SumByKey.of(dataset).keyBy(s -> s).output();
    final SumByKey sum = (SumByKey) TestUtils.getProducer(counted);
    assertFalse(sum.getName().isPresent());
  }