code: protected function renderV1()
      {
          if ('google' == $this->requestSource) {
              $out = [
                  'type'     => 'basic_card',
                  'platform' => $this->requestSource,
              ];
  
              if ($this->imageUrl) {
                  $out['image'] = [
                      'url'               => $this->imageUrl,
                      'accessibilityText' => 'accessibility text',
                  ];
              }
  
              return $out;
          } else {
              $out = [
                  'type'     => self::v1MessageObjectImage,
                  'platform' => $this->requestSource,
              ];
  
              if ($this->imageUrl) {
                  $out['imageUrl'] = $this->imageUrl;
              }
  
              return $out;
          }
      }
docs: Render response as array for API V1.
  
  @return array