public boolean isSuccess() {
    return httpStatus != null && httpStatus >= 200 && httpStatus < 300;
  }
@Test
  public void isSuccess_returns_true_if_http_response_returns_2xx_code() {
    WebhookDelivery delivery = newBuilderTemplate()
      .setHttpStatus(204)
      .build();

    assertThat(delivery.isSuccess()).isTrue();
  }