docs: protected int compareFiles(@NonNull File lhs, @NonNull File rhs) {
          if (lhs.isDirectory() && !rhs.isDirectory()) {
              return -1;
          } else if (rhs.isDirectory() && !lhs.isDirectory()) {
              return 1;
          } else {
              return lhs.getName().compareToIgnoreCase(rhs.getName());
          }
      }