public static function log($message, $level = Logger::INFO)
    {
        if (! self::$logger) {
            $logfile = sprintf('%s%sarrowsphere-client.log', sys_get_temp_dir(), DIRECTORY_SEPARATOR);
            
            // create a log channel
            self::$logger = new Logger('xAC');
            self::$logger->pushHandler(new StreamHandler($logfile, Logger::INFO));
        }
        
        return self::$logger->addRecord($level, $message);
    }