static function resolveFileResolvable(string $file) {
        $rfile = @\realpath($file);
        if($rfile) {
            if(self::$filesystem) {
                return self::$filesystem->getContents($file);
            }
            
            return \React\Promise\resolve(\file_get_contents($rfile));
        } elseif(\filter_var($file, FILTER_VALIDATE_URL)) {
            return \CharlotteDunois\Yasmin\Utils\URLHelpers::resolveURLToData($file);
        }
        
        return \React\Promise\reject(new \RuntimeException('Given file is not resolvable'));
    }