Does it work like elder.js?
The only resumable frameworks currently are Qwik and Marko6 (not released yet, beta coming Q1 2023)
Elder.js does partial hydration, which is similar to what Marko5, Astro or Fresh do. It basically means the server marks certain components (or component trees) as static, and tells the client to not hydrate them at all.
This works in reducing the amount of work the hydration has to do, and therefore making it quicker, but it doesn't do much for web applications with lots of interactivity.
In Amazon famous case, the 100ms delay was because it was an MPA: each page change was a page load. In that case I'd understand.
However, there are teams that have a lot of insight into the needs of ecommerce that are investing heavily in reducing the hydration overhead – I imagine the reason for it is that in very dynamic sites it feels clunky that the user can't interact with the page until it has hydrated.
It is no coincidence that the only other framework besides Qwik that is being built around resumability is eBay's Marko 6
They have probably influenced each other but I still feel like the claims about hydration might be kind of a red-herring.
For a complex application, data has to load in from the server on every page load – it can't simply be all bundled into the js.
In eBay's case, a MPA using their own custom framework makes sense, as they do async rendering (e.g. you can load and show the most important data in the page quickly, while ancilliary stuff can load afterwards) and partial hydration (so if a component doesn't require js, no js loads/runs)
The point is that hydration is more of an issue for MPAs since each time the page loads (on navigation), the html must be parsed and DOM objects need their javascript listeners attached.
For SPA, this is not the case after the initial page load event. Hydration needs to happen only once at startup.