code: @Override
      public final DoubleStream asDoubleStream() {
          return new DoublePipeline.StatelessOp<Long>(this, StreamShape.LONG_VALUE,
                                                      StreamOpFlag.NOT_SORTED | StreamOpFlag.NOT_DISTINCT) {
              @Override
              public Sink<Long> opWrapSink(int flags, Sink<Double> sink) {
                  return new Sink.ChainedLong<Double>(sink) {
                      @Override
                      public void accept(long t) {
                          downstream.accept((double) t);
                      }
                  };
              }
          };
      }
docs: Stateless intermediate ops from LongStream