FoldRegion @NotNull [] fetchCollapsedAt(int offset) {
    if (!isFoldingEnabled()) return FoldRegion.EMPTY_ARRAY;
    List<FoldRegion> allCollapsed = new ArrayList<>();
    myMarkerTree.processContaining(offset, region->{
      if (!region.isExpanded() && containsStrict(region, offset)) {
        allCollapsed.add(region);
      }
      return true;
    });
    return toFoldArray(allCollapsed);
  }
FoldRegion @NotNull [] fetchCollapsedAt(int offset)