code: @VisibleForTesting
    static String makeTargetStringForDirectAddress(SocketAddress address) {
      try {
        return new URI(DIRECT_ADDRESS_SCHEME, "", "/" + address, null).toString();
      } catch (URISyntaxException e) {
        // It should not happen.
        throw new RuntimeException(e);
      }
    }
docs: Returns a target string for the SocketAddress. It is only used as a placeholder, because
  DirectAddressNameResolverFactory will not actually try to use it. However, it must be a valid
  URI.