public function updateStats($stats, $delta = 1, $sampleRate = 1, array $tags = null)
    {
        if (!is_array($stats)) {
            $stats = array($stats);
        }
        $data = array();
        foreach ($stats as $stat) {
            $data[$stat] = "$delta|c";
        }
        return $this->send($data, $sampleRate, $tags);
    }