* versions.
   */
  public static Stats fromByteArray(byte[] byteArray) {
    checkNotNull(byteArray);
    checkArgument(
        byteArray.length == BYTES,
        "Expected Stats.BYTES = %s remaining , got %s",
        BYTES,
        byteArray.length);
    return readFrom(ByteBuffer.wrap(byteArray).order(ByteOrder.LITTLE_ENDIAN));
  }

  /**

        .addEqualityGroup(
            Stats.of(1.0, 1.0, 5.0, 5.0),
            Stats.of(1.0, 1.0, 5.0, 5.0),
            Stats.of(ImmutableList.of(1.0, 1.0, 5.0, 5.0)),
            Stats.of(ImmutableList.of(1.0, 1.0, 5.0, 5.0).iterator()),
            SerializableTester.reserialize(Stats.of(1.0, 1.0, 5.0, 5.0)))
        .addEqualityGroup(Stats.of(1.0, 5.0))
        .addEqualityGroup(Stats.of(1.0, 5.0, 1.0, 6.0))

    assertThat(EMPTY_PAIRED_STATS.toString())
        .isEqualTo("PairedStats{xStats=Stats{count=0}, yStats=Stats{count=0}}");
    assertThat(MANY_VALUES_PAIRED_STATS.toString())
        .isEqualTo(
            "PairedStats{xStats="
                + MANY_VALUES_PAIRED_STATS.xStats()
                + ", yStats="
                + MANY_VALUES_PAIRED_STATS.yStats()
                + ", populationCovariance="

   * the arithmetic mean of the population.
   *
   * @param values a nonempty series of values
   * @throws IllegalArgumentException if {@code values} is empty or contains any non-finite value
   * @deprecated Use {@link Stats#meanOf} instead, noting the less strict handling of non-finite
   *     values.
   */
  @Deprecated
  // com.google.common.math.DoubleUtils
  @GwtIncompatible
  public static double mean(double... values) {

        BYTES,
        byteArray.length);
    ByteBuffer buffer = ByteBuffer.wrap(byteArray).order(ByteOrder.LITTLE_ENDIAN);
    Stats xStats = Stats.readFrom(buffer);
    Stats yStats = Stats.readFrom(buffer);
    double sumOfProductsOfDeltas = buffer.getDouble();
    return new PairedStats(xStats, yStats, sumOfProductsOfDeltas);
  }

  private static final long serialVersionUID = 0;

          .doubleValue();

  // Stats instances:

  static final Stats EMPTY_STATS_VARARGS = Stats.of();
  static final Stats EMPTY_STATS_ITERABLE = Stats.of(ImmutableList.<Double>of());
  static final Stats ONE_VALUE_STATS = Stats.of(ONE_VALUE);
  static final Stats OTHER_ONE_VALUE_STATS = Stats.of(OTHER_ONE_VALUE);
  static final Stats TWO_VALUES_STATS = Stats.of(TWO_VALUES);

/**
 * Tests for {@link StatsAccumulator}. This tests the stats methods for instances built with {@link
 * StatsAccumulator#add} and {@link StatsAccumulator#addAll}, and various error cases of the {@link
 * StatsAccumulator#add} and {@link StatsAccumulator#addAll} methods. For tests of the {@link
 * StatsAccumulator#snapshot} method which returns {@link Stats} instances, see {@link StatsTest}.
 *
 * @author Pete Gillin
 */

    // Add two elements and invalidate them.
    cache.put(1, 4);
    cache.put(2, 8);

    cache.invalidateAll();

    assertEquals(2, stats[0]);
    assertEquals(2, stats[1]);
    assertEquals(4, stats[2]);
    assertEquals(3, stats[3]);
  }

  public void testPutAll() {
    Cache<Integer, Integer> cache = CacheBuilder.newBuilder().build();

    // Add two elements and invalidate them.
    cache.put(1, 4);
    cache.put(2, 8);

    cache.invalidateAll();

    assertEquals(2, stats[0]);
    assertEquals(2, stats[1]);
    assertEquals(4, stats[2]);
    assertEquals(3, stats[3]);
  }

  public void testPutAll() {
    Cache<Integer, Integer> cache = CacheBuilder.newBuilder().build();

 *             missCount}.
 *       </ul>
 *   <li>When an entry is evicted from the cache, {@code evictionCount} is incremented.
 *   <li>No stats are modified when a cache entry is invalidated or manually removed.
 *   <li>No stats are modified by operations invoked on the {@linkplain Cache#asMap asMap} view of
 *       the cache.
 * </ul>
 *