* Returns an immutable map containing the same entries as {@code map}, sorted by the natural
   * ordering of the keys.
   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *

   * Returns an immutable map containing the same entries as {@code map}, sorted by the natural
   * ordering of the keys.
   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *

        } while (oldHead != Waiter.TOMBSTONE);
      }
      // re-read value, if we get here then we must have observed a TOMBSTONE while trying to add a
      // waiter.
      // requireNonNull is safe because value is always set before TOMBSTONE.
      return getDoneValue(requireNonNull(value));
    }
    // If we get here then we have remainingNanos < SPIN_THRESHOLD_NANOS and there is no node on the
    // waiters list

   * iterable. The key used to store that value in the multimap will be the result of calling the
   * function on that value. The resulting multimap is created as an immutable snapshot. In the
   * returned multimap, keys appear in the order they are first encountered, and the values
   * corresponding to each key appear in the same order as they are encountered.
   *

      }
      // The cast is safe because of the hasPeeked check.
      return uncheckedCastNullableTToT(peekedElement);
    }
  }

  /**
   * Returns a {@code PeekingIterator} backed by the given iterator.
   *
   * <p>Calls to the {@code peek} method with no intervening calls to {@code next} do not affect the
   * iteration, and hence return the same object each time. A subsequent call to {@code next} is

  }

  /**
   * 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.
   *
   * @return a new, empty thread-safe {@code Set}
   * @since 15.0
   */

    new TypeVisitor() {
      @Override
      void visitTypeVariable(TypeVariable<?> type) {
        throw new IllegalArgumentException(
            runtimeType + "contains a type variable and is not safe for the operation");
      }

      @Override
      void visitWildcardType(WildcardType type) {
        visit(type.getLowerBounds());
        visit(type.getUpperBounds());
      }

      @Override

 * Cache} interfaces. The {@code asMap} view (and its collection views) have <i>weakly consistent
 * iterators</i>. This means that they are safe for concurrent use, but if other threads modify the
 * cache after the iterator is created, it is undefined which of these changes, if any, are

   * successful input futures. The list of results is in the same order as the input list, and if
   * any of the provided futures fails or is canceled, its corresponding position will contain
   * {@code null} (which is indistinguishable from the future having a successful value of {@code
   * null}).
   *
   * <p>The list of results is in the same order as the input list.
   *

   * the segment.
   */
  final transient int segmentMask;

  /**
   * Shift value for indexing within segments. Helps prevent entries that end up in the same segment
   * from also ending up in the same bucket.
   */
  final transient int segmentShift;

  /** The segments, each of which is a specialized hash table. */
  final transient Segment<K, V, E, S>[] segments;