Context: How does \Magento\Shipping\Controller\Adminhtml\Order\Shipment\Save::_saveShipment() work?
Details: How does \Magento\Sales\Model\ResourceModel\Order\Handler\State::check() work?
Details: How does \Magento\Payment\Observer\SalesOrderBeforeSaveObserver handle the sales_order_save_before event?
Details:
Details: How does \Magento\Framework\Model\ResourceModel\Db\VersionControl\AbstractDb::processAfterSaves() work for an order?