/** * Execute the server. * * @param callable $errorHandler The error handler callback. */ public function listen($errorHandler = null) { if (version_compare(PHP_VERSION, '5.4', '>=') && $this->handler instanceof \Closure) { $this->handler = $this->handler->bindTo($this); } $response = call_user_func($this->handler, $this->request, $this->response, $errorHandler); if (!$response instanceof ResponseInterface) { $response = $this->response; } $this->output->respond($response); }