private function getCallableResult()
    {
        if (is_callable($this->callback)) {
            return call_user_func_array($this->callback, (array) $this->callbackArguments);
        } elseif (is_string($this->callback) || $this->callback instanceof Markup) {
            // Insert the 'callback' as a string.
            return (string) $this->callback;
        }

        try {
            $msg = sprintf('Snippet loading failed with callable %s', Serialization::dump($this->callback));
        } catch (DumpException $e) {
            $msg = sprintf('Snippet loading failed with an unknown callback.');
        }

        throw new \RuntimeException($msg);
    }