private function getCommandString($command, array $arguments)
    {
        $list = [];
        foreach ($arguments as $argument) {
            $list[] = is_scalar($argument) ? $argument : '[.. complex type ..]';
        }

        return mb_substr(trim(strtoupper($command) . ' ' . $this->getPrefix() . implode(' ', $list)), 0, 256);
    }