@Override
    public @NotNull VirtualFileSet getFiles() {
      if (myFiles == null) {
        synchronized (this) {
          if (myFiles == null) {
            VirtualFileSet fileSet = VfsUtilCore.createCompactVirtualFileSet(myFilesSupplier.get());
            fileSet.freeze();
            myFilesSupplier = null;
            myFiles = fileSet;
          }
        }
      }
      return myFiles;
    }
@Override
    public @NotNull VirtualFileSet getFiles()