@UdafFactory(description = "collect distinct values of a Bigint field into a single Array")
  public static <T> Udaf<T, List<T>, List<T>> createCollectSetT() {
    return new Collect<>();
  }
@Test
  public void shouldCollectDistinctInts() {
    final Udaf<Integer, List<Integer>, List<Integer>> udaf = CollectSetUdaf.createCollectSetT();
    final Integer[] values = new Integer[] {3, 4, 5, 3};
    List<Integer> runningList = udaf.initialize();
    for (final Integer i : values) {
      runningList = udaf.aggregate(i, runningList);
    }
    assertThat(runningList, contains(3, 4, 5));
  }