@Deprecated
  public static UnboundedSource<Long, CounterMark> unbounded() {
    return unboundedWithTimestampFn(new NowTimestampFn());
  }
@Test
  @Category(NeedsRunner.class)
  public void testUnboundedSource() {
    long numElements = 1000;

    PCollection<Long> input =
        p.apply(Read.from(CountingSource.unbounded()).withMaxNumRecords(numElements));

    addCountingAsserts(input, numElements);
    p.run();
  }