}
  }

  /**
   * An {@link AbstractMultiset} with additional default implementations, some of them linear-time
   * implementations in terms of {@code elementSet} and {@code entrySet}.
   */
  private abstract static class ViewMultiset<E extends @Nullable Object>
      extends AbstractMultiset<E> {
    @Override
    public int size() {

    }
  }

  /**
   * An {@link AbstractMultiset} with additional default implementations, some of them linear-time
   * implementations in terms of {@code elementSet} and {@code entrySet}.
   */
  private abstract static class ViewMultiset<E extends @Nullable Object>
      extends AbstractMultiset<E> {
    @Override
    public int size() {

          // caught and forwarded to the service the task would stop executing but the service would
          // have no idea.
          // TODO(lukes): consider building everything in terms of ListenableScheduledFuture then
          // the AbstractService could monitor the future directly. Rescheduling is still hard...
          // but it would help with some of these lock ordering issues.

 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * java.util.Collection} contract, which is specified in terms of {@link Object#equals}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multiset">{@code Multiset}</a>.
 *
 * @author Louis Wasserman

 *
 * <h3>Capabilities</h3>
 *
 * <p>{@code Network} supports the following use cases (<a
 * href="https://github.com/google/guava/wiki/GraphsExplained#definitions">definitions of
 * terms</a>):
 *
 * <ul>
 *   <li>directed graphs
 *   <li>undirected graphs
 *   <li>graphs that do/don't allow parallel edges
 *   <li>graphs that do/don't allow self-loops

    Permissions perms = new Permissions();

    AdjustablePolicy(Permission... permissions) {
      for (Permission permission : permissions) perms.add(permission);
    }

    void addPermission(Permission perm) {
      perms.add(perm);
    }

    void clearPermissions() {
      perms = new Permissions();
    }

    @Override