code: private static IntConsumer adapt(Sink<Integer> sink) {
          if (sink instanceof IntConsumer) {
              return (IntConsumer) sink;
          }
          else {
  //            if (Tripwire.ENABLED)
  //                Tripwire.trip(AbstractPipeline.class,
  //                              "using IntStream.adapt(Sink<Integer> s)");
              return sink::accept;
          }
      }
docs: Adapt a {@code Sink<Integer> to an {@code IntConsumer}, ideally simply
  by casting.