return insertionOrder;
  }

  /**
   * Compares strings in natural order except that null comes immediately before a given value. This
   * works better than Ordering.natural().nullsFirst() because, if null comes before all other
   * values, it lies outside the submap/submultiset ranges we test, and the variety of tests that
   * exercise null handling fail on those subcollections.
   */

   */
  private static final class ThreadConfinedTaskQueue {
    /**
     * This field is only used for identity comparisons with the current thread. Field assignments
     * are atomic, but do not provide happens-before ordering; however:
     *
     * <ul>
     *   <li>If this field's value == currentThread, we know that it's up to date, because write
     *       operations in a thread always happen-before subsequent read operations in the same

 * average, in the marking phase, not {@code 5.0} as in {@code java.util.HashSet}.
 *
 * <p>If there are no removals, then {@link #iterator iteration} order is the same as insertion
 * order. Any removal invalidates any ordering guarantees.
 *
 * <p>This class should not be assumed to be universally superior to {@code java.util.HashSet}.
 * Generally speaking, this class reduces object allocation and memory consumption at the price of

   * computation is {@linkplain java.util.concurrent.Future#isDone() complete} or, if the
   * computation is already complete, immediately.
   *
   * <p>The callback is run on {@code executor}. There is no guaranteed ordering of execution of
   * callbacks, but any callback added through this method is guaranteed to be called once the
   * computation is complete.
   *
   * <p>Example:
   *
   * {@snippet :
   * future.addCallback(

    ImmutableListMultimap.Builder<String, Integer> builder = ImmutableListMultimap.builder();
    builder.put("bb", 3);
    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderKeysBy(
        new Ordering<String>() {
          @Override
          public int compare(String left, String right) {
            return left.length() - right.length();
          }
        });
    builder.put("cc", 4);

   * across different segments.
   *
   * The page replacement algorithm's data structures are kept casually consistent with the map. The
   * ordering of writes to a segment is sequentially consistent. An update to the map and recording
   * of reads may not be immediately reflected on the algorithm's data structures. These structures

  /**
   * Returns a comparator that compares two {@code char} arrays <a
   * href="http://en.wikipedia.org/wiki/Lexicographical_order">lexicographically</a>; not advisable
   * for sorting user-visible strings as the ordering may not match the conventions of the user's
   * locale. That is, it compares, using {@link #compare(char, char)}), the first pair of values

            }
            sort(
                (Entry<K, V>[]) entries, // Entries up to size are not null
                0,
                size,
                Ordering.from(valueComparator).onResultOf(Entry::getValue));
          }
          entriesUsed = true;
          return RegularImmutableBiMap.fromEntryArray(size, entries);
      }
    }

    /**

      strategyOrdinal = din.readByte();
      numHashFunctions = toUnsignedInt(din.readByte());
      dataLength = din.readInt();

      /*
       * We document in BloomFilterStrategies that we must not change the ordering, and we have a
       * test that verifies that we don't do so.
       */
      @SuppressWarnings("EnumOrdinal")
      Strategy strategy = BloomFilterStrategies.values()[strategyOrdinal];

    // These results are all incorrect, but there's no way (short of iterating over the result)
    // to verify that with an arbitrary ordering or comparator.
    assertEquals(ImmutableSortedMap.of(2, 0, 4, 0), Maps.subMap(map, Range.atLeast(4)));
    assertEquals(ImmutableSortedMap.of(8, 0, 10, 0), Maps.subMap(map, Range.atMost(8)));
    assertEquals(