public static GlobalDigest globally() {
    return GlobalDigest.builder().build();
  }
@Test
  public void globally() {
    PCollection<KV<Double, Double>> col =
        tp.apply(Create.of(stream))
            .apply(TDigestQuantiles.globally().withCompression(compression))
            .apply(ParDo.of(new RetrieveQuantiles(quantiles)));

    PAssert.that("Verify Accuracy", col).satisfies(new VerifyAccuracy());
    tp.run();
  }