* user-defined properties.
 *
 * <p>A {@code Network} built by this class has the following default properties:
 *
 * <ul>
 *   <li>does not allow parallel edges
 *   <li>does not allow self-loops
 *   <li>orders {@link Network#nodes()} and {@link Network#edges()} in the order in which the
 *       elements were added (insertion order)
 * </ul>
 *

   * class documentation above). This method is <i>generally expected</i>, but not absolutely
   * required, to have the following properties:
   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.

 * and performant but introduces some testing difficulties. This test exercises the two fallback
 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of

   * with as many copies of {@code padChar} as are necessary to reach that length. For example,
   *
   * <ul>
   *   <li>{@code padStart("7", 3, '0')} returns {@code "007"}
   *   <li>{@code padStart("2010", 3, '0')} returns {@code "2010"}
   * </ul>
   *
   * <p>See {@link java.util.Formatter} for a richer set of formatting capabilities.
   *

 * <h3>String utilities</h3>
 *
 * <ul>
 *   <li>{@link Ascii}
 *   <li>{@link CaseFormat}
 *   <li>{@link CharMatcher}
 *   <li>{@link Splitter}
 *   <li>{@link Strings}
 * </ul>
 *
 * <h3>Function types</h3>
 *
 * <ul>
 *   <li>{@link Converter}
 *   <li>{@link Equivalence}
 * </ul>
 *
 * <h3>Other</h3>
 *
 * <ul>
 *   <li>{@link Enums}
 *   <li>{@link MoreObjects}
 *   <li>{@link Preconditions}

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

 * <p>This tests:
 *
 * <ul>
 *   <li>comparing each object against itself returns true
 *   <li>comparing each object against null returns false
 *   <li>comparing each object against an instance of an incompatible class returns false
 *   <li>comparing each pair of objects within the same equality group returns true
 *   <li>comparing each pair of objects from different equality groups returns false
 *   <li>the hash codes of any two equal objects are equal

 *
 * <p>Valid:
 *
 * <ul>
 *   <li>Live: valid key/value are set
 *   <li>Loading: loading is pending
 * </ul>
 *
 * <p>Invalid:
 *
 * <ul>
 *   <li>Expired: time expired (key/value may still be set)
 *   <li>Collected: key/value was partially collected, but not yet cleaned up
 *   <li>Unset: marked as unset, awaiting cleanup or reuse
 * </ul>
 */
@GwtIncompatible

  }

  /**
   * Returns a fresh instance for {@code type} if possible. The returned instance could be:
   *
   * <ul>
   *   <li>exactly of the given type, including generic type parameters, such as {@code
   *       ImmutableList<String>};
   *   <li>of the raw type;
   *   <li>null if no value can be generated.
   * </ul>
   */
  final @Nullable Object generateFresh(TypeToken<?> type) {