Discussion: Improving hydration performance for large lists

Description

When working with large lists (1000+ items) in SvelteKit, hydration can be noticeably slow compared to the initial SSR render. This affects Time to Interactive (TTI) metrics significantly.

Reproduction

Rendering a list of 2000 items with dynamic content shows a 300-500ms hydration delay on mid-range devices.

Suggestion

Consider implementing virtual hydration or lazy hydration strategies:

1. Only hydrate visible items initially
2. Defer hydration of off-screen items until they enter the viewport
3. Provide a lazy directive for components that can be hydrated later

This would significantly improve TTI for content-heavy pages like e-commerce listings or social feeds.