private function getImpressionParams(Experiment $experiment, $variationId)
    {
        $impressionParams = [
            DECISIONS => [
                [
                    CAMPAIGN_ID => $experiment->getLayerId(),
                    EXPERIMENT_ID => $experiment->getId(),
                    VARIATION_ID => $variationId
                ]
            ],

            EVENTS => [
                [
                    ENTITY_ID => $experiment->getLayerId(),
                    TIMESTAMP => time()*1000,
                    UUID => GeneratorUtils::getRandomUuid(),
                    KEY => ACTIVATE_EVENT_KEY
                ]
            ]

        ];

        return $impressionParams;
    }