code: public function overlay($title, $message, $level = 'info', $key = 'flash_message')
      {
          return $this->create($title, $message, $level, $key.'_overlay');
      }
docs: Flash an overlay modal.
  
  @param string $title
  @param string $message
  @param string $level
  @param string $key
  
  @return $this