code: protected function renderV1()
      {
          if ('google' == $this->requestSource) {
              $out = [
                  'type'     => 'basic_card',
                  'platform' => $this->requestSource,
                  'title'    => $this->title,
              ];
  
              if (! $this->text && ! $this->imageUrl) {
                  $out['formattedText'] = ' '; // AoG requires text or image in card
              }
  
              if ($this->text) {
                  $out['formattedText'] = $this->text;
              }
  
              if ($this->imageUrl) {
                  $out['image'] = [
                      'url'               => $this->imageUrl,
                      'accessibilityText' => 'accessibility text',
                  ];
              }
  
              if ($this->buttons) {
                  $out['buttons'] = [];
                  foreach ($this->buttons as $button) {
                      $out['buttons'][] =
                          [
                              'title'         => $button['buttonText'],
                              'openUrlAction' => [
                                  'url' => $button['buttonUrl'],
                              ],
                          ];
                  }
              }
  
              return $out;
          } else {
              $out = [
                  'type'  => self::v1MessageObjectCard,
                  'title' => $this->title,
              ];
  
              if ($this->text) {
                  $out['subtitle'] = $this->text;
              }
              if ($this->imageUrl) {
                  $out['imageUrl'] = $this->imageUrl;
              }
  
              // this is required in the response even if there are no buttons for some reason
              if ('slack' == $this->requestSource) {
                  $out['buttons'] = [];
              }
  
              if ($this->buttons) {
                  $out['buttons'] = [];
                  foreach ($this->buttons as $button) {
                      $out['buttons'][] =
                          [
                              'text'     => $button['buttonText'],
                              'postback' => $button['buttonUrl'],
                          ];
                  }
              }
  
              $out['platform'] = $this->requestSource;
  
              return $out;
          }
      }
docs: Render response as array for API V1.
  
  @return array