* Iterator#remove} operations. This utility takes the brute-force approach of trying <i>all</i>
 * possible sequences of these operations, up to a given number of steps. So, if the caller
 * specifies to use <i>n</i> steps, a total of <i>3^n</i> tests are actually performed.
 *
 * <p>For instance, if <i>steps</i> is 5, one example sequence that will be tested is:
 *
 * <ol>
 *   <li>remove();

   * themselves their proper values under GWT, since GWT's EnumMap does need the Class instance.
   *
   * Note that sometimes these fields *do* have correct values under J2CL: They will if the caller
   * calls `create(Foo.class)`, rather than `create(map)`. That's fine; we just shouldn't rely on
   * it.
   */
  transient Class<K> keyTypeOrObjectUnderJ2cl;
  transient Class<V> valueTypeOrObjectUnderJ2cl;

  /**

    return new MutableClassToInstanceMap<>(new HashMap<Class<? extends @NonNull B>, B>());
  }

  /**
   * Returns a new {@code MutableClassToInstanceMap} instance backed by a given empty {@code
   * backingMap}. The caller surrenders control of the backing map, and thus should not allow any
   * direct references to it to remain accessible.
   */
  public static <B extends @Nullable Object> MutableClassToInstanceMap<B> create(

    }
  }

  /**
   * Views the array as an immutable list. The array must have only {@code E} elements.
   *
   * <p>The array must be internally created.
   */
  @SuppressWarnings("unchecked") // caller is reponsible for getting this right
  static <E> ImmutableList<E> asImmutableList(Object[] elements) {
    return unsafeDelegateList((List) Arrays.asList(elements));
  }

   * advantages to having the type are the ability to use its constructor reference below and the
   * parallelism with the primitive version. In short, it makes its caller ({@code flatMap})
   * simpler.
   *
   * @param <InElementT> the element type of the input spliterator
   * @param <OutElementT> the element type of the output spliterators
   */

   * Optional.orElseGet}, except when {@code supplier} returns {@code null}. In this case this
   * method throws an exception, whereas the Java 8+ method returns the {@code null} to the caller.
   *
   * @throws NullPointerException if this optional's value is absent and the supplier returns {@code
   *     null}
   */
  public abstract T or(Supplier<? extends T> supplier);

  /**

    /**
     * It is implicitly assumed that all the services are NEW and that they will all remain NEW
     * until all the Listeners are installed and {@link #markReady()} is called. It is our caller's
     * responsibility to only call {@link #markReady()} if all services were new at the time this
     * method was called and when all the listeners were installed.
     */

   * The {@link Iterators} analog to this method is {@link Iterators#getNext}.
   *
   * <p>If no default value is desired (and the caller instead wants a {@link
   * NoSuchElementException} to be thrown), it is recommended that {@code
   * iterable.iterator().next()} is used instead.
   *

   * PeekingIterator#remove()}.
   *
   * <p>Note: If the given iterator is already a {@code PeekingIterator}, it <i>might</i> be
   * returned to the caller, although this is neither guaranteed to occur nor required to be
   * consistent. For example, this method <i>might</i> choose to pass through recognized

        // ignore
      }
    }
  }

  /**
   * Cleans up the given reference and any other references already in the queue. Catches and logs
   * all throwables.
   *
   * @return true if the caller should continue to wait for more references to be added to the
   *     queue, false if the associated FinalizableReferenceQueue is no longer referenced.
   */
  private boolean cleanUp(Reference<?> firstReference) {