public function processMultipleRegions() {
        return new Pool($this->client, $this->requests, [
            'concurrency' => 18,
            'fulfilled'   => function ($response, $index) {
                array_push($this->acceptedResponsesJson, json_decode($response->getBody()->getContents()));
            },
            'rejected'    => function ($reason, $index)  {
                array_push($this->rejectedResponse, $reason);
            },
        ]);
    }