import javax.annotation.CheckForNull;

/**
 * A bundle of statistical summary values -- sum, count, mean/average, min and max, and several
 * forms of variance -- that were computed from a single set of zero or more floating-point values.
 *
 * <p>There are two ways to obtain a {@code Stats} instance:
 *
 * <ul>
 *   <li>If all the values you want to summarize are already known, use the appropriate {@code

    ConcurrentHashMultiset<String> multiset = ConcurrentHashMultiset.create(map);

    String s1 = new String("a");
    String s2 = new String("a");
    assertEquals(s1, s2); // Stating the obvious.
    assertTrue(s1 != s2); // Stating the obvious.

    multiset.add(s1);
    assertTrue(multiset.contains(s1));
    assertFalse(multiset.contains(s2));
    assertEquals(1, multiset.count(s1));

    }

    @Override
    @ParametricNullness
    public T get() {
      // Another variant of Double Checked Locking.
      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;

    public EntryComparator(@Nullable Comparator<? super K> keyComparator) {
      this.keyComparator = keyComparator;
    }

    @Override
    @SuppressWarnings("unchecked") // no less safe than putting it in the map!
    public int compare(Entry<K, V> a, Entry<K, V> b) {
      return (keyComparator == null)
          ? ((Comparable) a.getKey()).compareTo(b.getKey())
          : keyComparator.compare(a.getKey(), b.getKey());

  // If the `next` bits in `entries[i]` are 0 that means there are no further entries for the given
  // short hash. But 0 is also a valid index in `entries`, so we add 1 to these indices before
  // putting them in `table` or in `next` bits, and subtract 1 again when we need an index value.
  //
  // The elements of `keys`, `values`, and `entries` are added sequentially, so that elements 0 to