} else {
      return set(set, mutex);
    }
  }

  static final class SynchronizedAsMapEntries<
          K extends @Nullable Object, V extends @Nullable Object>
      extends SynchronizedSet<Map.Entry<K, Collection<V>>> {
    SynchronizedAsMapEntries(
        Set<Map.Entry<K, Collection<V>>> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }

    } else {
      return set(set, mutex);
    }
  }

  static final class SynchronizedAsMapEntries<
          K extends @Nullable Object, V extends @Nullable Object>
      extends SynchronizedSet<Map.Entry<K, Collection<V>>> {
    SynchronizedAsMapEntries(
        Set<Map.Entry<K, Collection<V>>> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }