Product data comes from the same simulated server as steps 3 and 4.

Loading products…

Couldn't load products.

Showing of products

Saving…

Reload this page (Cmd/Ctrl+R). The list is there instantly, with the quantities from before you reloaded, before the network request even finishes. A moment later they jump to the server's fresh numbers. That correction is isStale resolving; the one new line making it possible is below: persist: true.