docs: public static boolean isLegacyIndexingEnabled(Descriptor messageDescriptor) {
        boolean isLegacyIndexingEnabled = true;
        for (Option o : messageDescriptor.getFileDescriptor().getOptions()) {
           if (o.getName().equals(INDEXED_BY_DEFAULT_OPTION)) {
              isLegacyIndexingEnabled = Boolean.valueOf((String) o.getValue());
              break;
           }
        }
        return isLegacyIndexingEnabled;
     }