code: private static Spliterator.OfLong adapt(Spliterator<Long> s) {
          if (s instanceof Spliterator.OfLong) {
              return (Spliterator.OfLong) s;
          } else {
  //            if (Tripwire.ENABLED)
  //                Tripwire.trip(AbstractPipeline.class,
  //                              "using LongStream.adapt(Spliterator<Long> s)");
              throw new UnsupportedOperationException("LongStream.adapt(Spliterator<Long> s)");
          }
      }
docs: Adapt a {@code Spliterator<Long>} to a {@code Spliterator.OfLong}.
  
  @implNote
  The implementation attempts to cast to a Spliterator.OfLong, and throws
  an exception if this cast is not possible.