private function createRequestOrderXML( OrderRequest $order )
    {
        $xmlWriter = new XMLWriter;

        $xmlWriter->openMemory();
        $xmlWriter->startDocument( '1.0', 'UTF-8' );

        $order->toXML( $xmlWriter );

        $xmlWriter->endDocument();

        return $xmlWriter->outputMemory( true );
    }
private function createRequestOrderXML( OrderRequest $order )
    {
        $xmlWriter = new XMLWriter;

        $xmlWriter->openMemory();
        $xmlWriter->startDocument( '1.0', 'UTF-8' );

        $order->toXML( $xmlWriter );

        $xmlWriter->endDocument();

        return $xmlWriter->outputMemory( true );
    }
@param  \RodrigoPedra\ClearSaleID\Entity\Request\Order $order

@return string
@throws \RodrigoPedra\ClearSaleID\Exception\RequiredFieldException