@Override
  public @NotNull MapReduceIndexBase<Integer, SerializedStubTree, ?> createIndex(@NotNull FileBasedIndexExtension<Integer, SerializedStubTree> extension,
                                                                                 @NotNull VfsAwareIndexStorageLayout<Integer, SerializedStubTree> layout,
                                                                                 @NotNull SerializationManagerEx serializationManager)
    throws IOException {
    return new StubUpdatingIndexStorage(extension, layout, serializationManager);
  }
@Override
  public @NotNull MapReduceIndexBase<Integer, SerializedStubTree, ?> createIndex(@NotNull FileBasedIndexExtension<Integer, SerializedStubTree> extension,
                                                                                 @NotNull VfsAwareIndexStorageLayout<Integer, SerializedStubTree> layout,
                                                                                 @NotNull SerializationManagerEx serializationManager)