protected function getMetricIndicator(AbstractMetric $metric)
    {
        switch ($metric->getType()) {
            case Set::TYPE:       return 's';
            case Gauge::TYPE:     return 'g';
            case Timer::TYPE:     return 'ms';
            case Counter::TYPE:   return 'c';
            case Histogram::TYPE: return 'h';

            default:
                throw new \InvalidArgumentException('Metric type is not a valid DataDog metric: '.$metric->getType());
        }
    }