docs: @Restricted(NoExternalUse.class)
      public @Nonnull List<VirtualFile> listOnlyDescendants() throws IOException {
          VirtualFile[] children = list();
          List<VirtualFile> result = new ArrayList<>();
          for (VirtualFile child : children) {
              if (child.isDescendant("")) {
                  result.add(child);
              }
          }        
          return result;
      }