src/Server/Router/Endpoint/ResourceEndpoint/ResourceAPIResponseDataFactory.php
public function multipleToAPIResponseData(?array $resources): APIResponseData
    {
        if(is_null($resources)) {
            return $this->toAPIResponseData(null);
        }

        return new APIResponseData(array_map(function(Resource $resource) {
            return $this->toAPIResponseData($resource)->getData();
        }, $resources));
    }
public function multipleToAPIResponseData(?array $resources): APIResponseData
    {
        if(is_null($resources)) {
            return $this->toAPIResponseData(null);
        }

        return new APIResponseData(array_map(function(Resource $resource) {
            return $this->toAPIResponseData($resource)->getData();
        }, $resources));
    }
Uses above method for each resource, extracting the data into an array, creating a new APIResponseData from that array.
@param null|Resource[] $resources
@return APIResponseData
@throws UnableToCreateAPIResponseDataException