Backend\Modules\Analytics\GoogleClient\Connector::getMetrics PHP Method

    private function getMetrics($startDate, $endDate)
    {
        $metrics = $this->getAnalyticsData($startDate, $endDate, 'ga:pageviews,ga:users,ga:pageviewsPerSession,ga:avgSessionDuration,ga:percentNewSessions,ga:bounceRate');
        return $metrics['totalsForAllResults'];
    }