return CollectCollectors.toImmutableSortedMap(
        comparator, keyFunction, valueFunction, mergeFunction);
  }

  /*
   * TODO(kevinb): Confirm that ImmutableSortedMap is faster to construct and
   * uses less memory than TreeMap; then say so in the class Javadoc.
   */
  private static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  private static final ImmutableSortedMap<Comparable<?>, Object> NATURAL_EMPTY_MAP =

   * @param size the size of that array, list or string
   * @return the value of {@code index}
   * @throws IndexOutOfBoundsException if {@code index} is negative or is not less than {@code size}
   * @throws IllegalArgumentException if {@code size} is negative
   */
  @CanIgnoreReturnValue
  public static int checkElementIndex(int index, int size) {

   * any of the public methods of ListenableFuture.
   */
  interface Trusted<V extends @Nullable Object> extends ListenableFuture<V> {}

  /**
   * A less abstract subclass of AbstractFuture. This can be used to optimize setFuture by ensuring
   * that {@link #get} calls exactly the implementation of {@link AbstractFuture#get}.
   */

   * any of the public methods of ListenableFuture.
   */
  interface Trusted<V extends @Nullable Object> extends ListenableFuture<V> {}

  /**
   * A less abstract subclass of AbstractFuture. This can be used to optimize setFuture by ensuring
   * that {@link #get} calls exactly the implementation of {@link AbstractFuture#get}.
   */

    return CollectCollectors.toImmutableSortedMap(
        comparator, keyFunction, valueFunction, mergeFunction);
  }

  /*
   * TODO(kevinb): Confirm that ImmutableSortedMap is faster to construct and
   * uses less memory than TreeMap; then say so in the class Javadoc.
   */
  private static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  private static final ImmutableSortedMap<Comparable<?>, Object> NATURAL_EMPTY_MAP =

   * @param size the size of that array, list or string
   * @return the value of {@code index}
   * @throws IndexOutOfBoundsException if {@code index} is negative or is not less than {@code size}
   * @throws IllegalArgumentException if {@code size} is negative
   */
  @CanIgnoreReturnValue
  public static int checkElementIndex(int index, int size) {

     * traverse. When nodes would otherwise be changed, new nodes are created to replace them. This
     * works well for hash tables since the bin lists tend to be short. (The average length is less
     * than two.)
     *
     * Read operations can thus proceed without locking, but rely on selected uses of volatiles to
     * ensure that completed write operations performed by other threads are noticed. For most

   */
  public static CharMatcher breakingWhitespace() {
    return BreakingWhitespace.INSTANCE;
  }

  /**
   * Determines whether a character is ASCII, meaning that its code point is less than 128.
   *
   * @since 19.0 (since 1.0 as constant {@code ASCII})
   */
  public static CharMatcher ascii() {
    return Ascii.INSTANCE;
  }

  /**

    int skipped = advance(iterator, position);
    if (!iterator.hasNext()) {
      throw new IndexOutOfBoundsException(
          "position ("
              + position
              + ") must be less than the number of elements that remained ("
              + skipped
              + ")");
    }
    return iterator.next();
  }

  /**

   */
  public static CharMatcher breakingWhitespace() {
    return BreakingWhitespace.INSTANCE;
  }

  /**
   * Determines whether a character is ASCII, meaning that its code point is less than 128.
   *
   * @since 19.0 (since 1.0 as constant {@code ASCII})
   */
  public static CharMatcher ascii() {
    return Ascii.INSTANCE;
  }

  /**