1". */ const ABORT = 'abort'; /** * @var string */ private $url; /** * @var callable|null */ private $before; /** * @param string $url */ public function __construct($url) { $this->url = $url; } public function before($callable) { $this->before = $callable; } public function start() { if ($this->before) { return call_user_func($this->before); } } public function __toString() { return $this->url; } }