code: public function renderBodyBegin()
      {
          $lines[] = $this->renderCloseButton();
          if ($this->icon !== null) {
              $lines[] = $this->icon;
          }
          $lines[] = $this->renderHeader();
  
          return implode("\n", $lines);
      }
docs: Renders the close button and its header (if any)
  
  @return string the begin of the body