protected function createNormalizedArray(array $rawPayload, AdapterInterface $adapter)
    {
        $metadata = $this->extractMetadata($rawPayload, $adapter);
        // @todo Should this be wrapped in an object, or is a hash fine?
        return [
            'id'            => $this->extractId($rawPayload),
            'type'          => $metadata->type,
            'properties'    => $this->extractProperties($rawPayload, $metadata)
        ];
    }