protected function _extractQuoteSkuData(Mage_Sales_Model_Quote $quote)
    {
        $skuData = [];
        // use getAllVisibleItems to prevent dupes due to parent config + child used both being included
        foreach ($quote->getAllVisibleItems() as $item) {
            // before item's have been saved, getAllVisible items won't properly
            // filter child items...this extra check fixes it
            if ($item->getParentItem()) {
                continue;
            }
            $skuData[$item->getSku()] = [
                'item_id' => $item->getId(),
                'managed' => Mage::helper('radial_core/quote_item')->isItemInventoried($item),
                'virtual' => $item->getIsVirtual(),
                'qty' => $item->getQty(),
            ];
        }
        return $skuData;
    }