.post(ProgressRequestBody(requestBody, progressListener))
        .build()

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")
      println(response.body.string())
    }
  }

  private class ProgressRequestBody(
    private val delegate: RequestBody,
    private val progressListener: ProgressListener,
  ) : RequestBody() {

  }

  private static class ProgressRequestBody extends RequestBody {

    private final ProgressListener progressListener;
    private final RequestBody delegate;

    public ProgressRequestBody(RequestBody delegate, ProgressListener progressListener) {
      this.delegate = delegate;
      this.progressListener = progressListener;
    }

    @Override
    public MediaType contentType() {
      return delegate.contentType();

    private final ResponseBody responseBody;
    private final ProgressListener progressListener;
    private BufferedSource bufferedSource;

    ProgressResponseBody(ResponseBody responseBody, ProgressListener progressListener) {
      this.responseBody = responseBody;
      this.progressListener = progressListener;
    }

    @Override public MediaType contentType() {
      return responseBody.contentType();