* values are merged using the specified merging function. If the merging function returns {@code
   * null}, then the collector removes the value that has been computed for the key thus far (though
   * future occurrences of the key would reinsert it).
   *
   * <p>Entries will appear in the encounter order of the first occurrence of the key.
   *
   * @since 21.0
   */

 * with {@link Collection} itself). Prefer subtypes such as {@link ImmutableSet} or {@link
 * ImmutableList}, which have well-defined {@link #equals} semantics, thus avoiding a common source
 * of bugs and confusion.
 *
 * <h3>About <i>all</i> {@code Immutable-} collections</h3>
 *
 * <p>The remainder of this documentation applies to every public {@code Immutable-} type in this

     * regrettable implementations like our own Sets.filter, Collection.size() is sometimes a
     * linear-time operation, and it can even have side effects. Thus, we limit the special case to
     * List, which is _even more likely_ to have size() implemented to be fast and side-effect-free.
     *

     * to eliminate copying data when writing NbtSession data one might
     * manage that 4 byte header specifically and therefore the initial
     * bufferIndex, and thus headerStart, would be 4).(NOTE: If one where
     * looking for a way to improve perfomance this is precisly what you
     * would want to do as the jcifs.netbios.SocketXxxputStream classes

   * each providing an element of the multiset and the count of that element. This set contains
   * exactly one entry for each distinct element in the multiset (thus it always has the same size
   * as the {@link #elementSet}). The order of the elements in the element set is unspecified.
   *
   * <p>The entry set is backed by the same data as the multiset, so any change to either is

        return unsafeNull(); // See the discussion in getValue().
      }
      /*
       * The cast is safe because updateIndex found the entry for this key. (If it hadn't, then we
       * would have returned above.) Thus, we know that it and its corresponding value are in
       * position `index`.
       */
      V oldValue = uncheckedCastNullableTToT(values[index]);
      if (Objects.equals(oldValue, value)) {
        return value;

  /** Returns the total number of stripes in this instance. */
  public abstract int size();

  /**
   * Returns the stripes that correspond to the passed objects, in ascending (as per {@link
   * #getAt(int)}) order. Thus, threads that use the stripes in the order returned by this method
   * are guaranteed to not deadlock each other.
   *
   * <p>It should be noted that using a {@code Striped<L>} with relatively few stripes, and {@code

  /*
   * @IgnoreJRERequirement should be redundant with the one on Streams itself, but it's necessary as
   * of Animal Sniffer 1.24. Maybe Animal Sniffer processes this nested class before it processes
   * Streams and thus hasn't had a chance to see Streams's annotation?
   */
  @IgnoreJRERequirement
  private abstract static class MapWithIndexSpliterator<
          F extends Spliterator<?>,
          R extends @Nullable Object,

   * each providing an element of the multiset and the count of that element. This set contains
   * exactly one entry for each distinct element in the multiset (thus it always has the same size
   * as the {@link #elementSet}). The order of the elements in the element set is unspecified.
   *
   * <p>The entry set is backed by the same data as the multiset, so any change to either is

      int expectedSize) {
    return new HashSet<>(Maps.capacity(expectedSize));
  }

  /**
   * Creates a thread-safe set backed by a hash map. The set is backed by a {@link
   * ConcurrentHashMap} instance, and thus carries the same concurrency guarantees.
   *
   * <p>Unlike {@code HashSet}, this class does NOT allow {@code null} to be used as an element. The
   * set is serializable.
   *