.url("http://publicobject.com/helloworld.txt")
        .build();

    client.newCall(request).enqueue(new Callback() {
      @Override public void onFailure(Call call, IOException e) {
        e.printStackTrace();
      }

      @Override public void onResponse(Call call, Response response) throws IOException {
        try (ResponseBody responseBody = response.body()) {

            .url("http://publicobject.com/helloworld.txt")
            .build()

        client.newCall(request).enqueue(object : Callback {
          override fun onFailure(call: Call, e: IOException) {
            e.printStackTrace()
          }

          override fun onResponse(call: Call, response: Response) {
            response.use {
              if (!response.isSuccessful) throw IOException("Unexpected code $response")