}

  /**
   * Implements {@code Collection.contains} safely for forwarding collections of map entries. If
   * {@code o} is an instance of {@code Entry}, it is wrapped using {@link #unmodifiableEntry} to
   * protect against a possible nefarious equals method.
   *
   * <p>Note that {@code c} is the backing (delegate) collection, rather than the forwarding
   * collection.
   *