@Override
  public void expand(final VirtualFile file, final @Nullable Runnable onDone) {
    TreeUtil.promiseExpand(myTree, new FileNodeVisitor(file)).onSuccess(path -> {
      if (path != null && onDone != null) onDone.run();
    });
  }
@Override
  public void expand(final VirtualFile file, final @Nullable Runnable onDone)