@SuppressLint("NewApi")
  override fun getSelectedProtocol(sslSocket: SSLSocket): String? {
    return try {
      // SSLSocket.getApplicationProtocol returns "" if application protocols values will not
      // be used. Observed if you didn't specify SSLParameters.setApplicationProtocols
      when (val protocol = sslSocket.applicationProtocol) {
        null, "" -> null
        else -> protocol
      }