code: public function setButton($payload)
      {
          $model = new Button();
  
          $model->setType(!empty($payload['type']) ? $payload['type'] : 'web_url');
  
          if (!empty($payload['title'])) {
              $model->setTitle($payload['title']);
          }
  
          if (!empty($payload['payload'])) {
              $model->setPayload($payload['payload']);
          }
  
          if (!empty($payload['url'])) {
              $model->setUrl($payload['url']);
          }
  
          $this->buttons[] = $model;
      }
docs: Set button
  
  @param array $payload Payload