* first over all the elements of {@code set1}, then over each element of {@code set2}, in order,
   * that is not contained in {@code set1}.
   *
   * <p>Results are undefined if {@code set1} and {@code set2} are sets based on different
   * equivalence relations, for example if {@code set1} is a {@link HashSet} and {@code set2} is a
   * {@link TreeSet} or the {@link Map#keySet} of an {@code IdentityHashMap}.
   */

 * <p><b>Warning:</b> This class deals only with {@code char} values, that is, <a
 * href="http://www.unicode.org/glossary/#BMP_character">BMP characters</a>. It does not understand
 * <a href="http://www.unicode.org/glossary/#supplementary_code_point">supplementary Unicode code
 * points</a> in the range {@code 0x10000} to {@code 0x10FFFF} which includes the majority of
 * assigned characters, including important CJK characters and emoji.
 *

    S newSegment(MapMakerInternalMap<K, V, E, S> map, int initialCapacity);

    /**
     * Returns a freshly created entry, typed at the {@code E} type, for the given {@code segment}.
     */
    E newEntry(S segment, K key, int hash, @CheckForNull E next);

    /**
     * Returns a freshly created entry, typed at the {@code E} type, for the given {@code segment},

     * profiles from the project's POM and all its parent POMs as well as from external sources like the
     * {@code settings.xml}. The profile identifiers are grouped by the identifier of their source, e.g.
     * {@code <groupId>:<artifactId>:<version>} for a POM profile or {@code external} for profiles from the
     * {@code settings.xml}.
     *

   * throwing an exception, if passed a {@code toKey} greater than an earlier {@code toKey}.
   */
  @Override
  public ImmutableSortedMap<K, V> subMap(K fromKey, K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  /**
   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges

   * @throws IllegalArgumentException if {@code size} is negative
   */
  @CanIgnoreReturnValue
  public static int checkElementIndex(int index, int size) {
    return checkElementIndex(index, size, "index");
  }

  /**
   * Ensures that {@code index} specifies a valid <i>element</i> in an array, list or string of size

   * throwing an exception, if passed a {@code toKey} greater than an earlier {@code toKey}.
   */
  @Override
  public ImmutableSortedMap<K, V> subMap(K fromKey, K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  /**
   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges

  }

  /**
   * Sets the result of this {@code Future} unless this {@code Future} has already been cancelled or
   * set (including {@linkplain #setFuture set asynchronously}). When a call to this method returns,
   * the {@code Future} is guaranteed to be {@linkplain #isDone done} <b>only if</b> the call was
   * accepted (in which case it returns {@code true}). If it returns {@code false}, the {@code

  /**
   * Returns an iterator that cycles indefinitely over the elements of {@code iterable}.
   *
   * <p>The returned iterator supports {@code remove()} if the provided iterator does. After {@code
   * remove()} is called, subsequent cycles omit the removed element, which is no longer in {@code
   * iterable}. The iterator's {@code hasNext()} method returns {@code true} until {@code iterable}
   * is empty.
   *

  /**
   * Test-helper method that performs {@code nThreads} concurrent calls to {@code cache.get(key)} or
   * {@code cache.getUnchecked(key)}, and returns a List containing each of the results. The result
   * for any given call to {@code cache.get} or {@code cache.getUnchecked} is the value returned, or
   * the exception thrown.
   *
   * <p>As we iterate from {@code 0} to {@code nThreads}, threads with an even index will call