code: private function getContentFields(Content $content)
      {
          $fields = [];
  
          if ($this->contentFieldMapper->accept($content)) {
              $fields = $this->contentFieldMapper->mapFields($content);
          }
  
          return $fields;
      }
docs: Returns an array of fields for the given $content, to be added to the corresponding
  Content document.
  
  @param \eZ\Publish\SPI\Persistence\Content $content
  
  @return \eZ\Publish\SPI\Search\Field[]