StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(MANY_VALUES);
    Stats stats = accumulator.snapshot();
    accumulator.add(999.999); // should do nothing to the snapshot
    return stats;
  }

  private static Stats buildLongManyValuesStatsSnapshot() {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(LONG_MANY_VALUES);

    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(MANY_VALUES);
    Stats stats = accumulator.snapshot();
    accumulator.add(999.999); // should do nothing to the snapshot
    return stats;
  }

  private static Stats buildLongManyValuesStatsSnapshot() {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(LONG_MANY_VALUES);

  public void testCountOverflow_doesNotThrow() {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.add(ONE_VALUE);
    for (int power = 1; power < Long.SIZE - 1; power++) {
      accumulator.addAll(accumulator.snapshot());
    }
    // Should overflow without throwing.
    accumulator.addAll(accumulator.snapshot());
    assertThat(accumulator.count()).isLessThan(0L);
  }

  public void testMean() {

  public void testCountOverflow_doesNotThrow() {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.add(ONE_VALUE);
    for (int power = 1; power < Long.SIZE - 1; power++) {
      accumulator.addAll(accumulator.snapshot());
    }
    // Should overflow without throwing.
    accumulator.addAll(accumulator.snapshot());
    assertThat(accumulator.count()).isLessThan(0L);
  }

  public void testMean() {

        createTestIndex();

        List<String> results = ScrollOperationHelper.scrollSearch(client, suggester.settings(), INDEX_NAME, QueryBuilders.matchAllQuery(),
                10, (hit, accumulator) -> accumulator.add(hit.getId()));

        assertNotNull(results);
        assertTrue(results.isEmpty());
    }

    @Test
    public void testScrollSearch_singlePage() {
        createTestIndex();

    PairedStatsAccumulator accumulator = new PairedStatsAccumulator();
    accumulator.add(ONE_VALUE, OTHER_ONE_VALUE);
    for (int power = 1; power < Long.SIZE - 1; power++) {
      accumulator.addAll(accumulator.snapshot());
    }
    // Should overflow without throwing.
    accumulator.addAll(accumulator.snapshot());
    assertThat(accumulator.count()).isLessThan(0L);
  }

        A accum = collector.supplier().get();
        for (T input : inputs) {
          collector.accumulator().accept(accum, input);
        }
        return accum;
      }
    },
    /** Get one accumulator for each element and merge the accumulators left-to-right. */
    MERGE_LEFT_ASSOCIATIVE {
      @Override
      final <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>

        A accum = collector.supplier().get();
        for (T input : inputs) {
          collector.accumulator().accept(accum, input);
        }
        return accum;
      }
    },
    /** Get one accumulator for each element and merge the accumulators left-to-right. */
    MERGE_LEFT_ASSOCIATIVE {
      @Override
      final <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>

    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(values);
    return accumulator.snapshot();
  }

  /**
   * Returns statistics over a dataset containing the given values.
   *
   * @param values a series of values
   */
  public static Stats of(double... values) {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(values);

     *
     * @param <T> The type of item to accumulate
     */
    @FunctionalInterface
    public interface HitProcessor<T> {
        /**
         * Process a single search hit and optionally add results to the accumulator.
         *
         * @param hit The search hit to process
         * @param accumulator The list to accumulate results
         */
        void process(SearchHit hit, List<T> accumulator);