What problem does it solve? Partial prerendering (PPR) makes first paint instant, but React still hydrates the whole page as one long synchronous main-thread task, leaving the page unresponsive for seconds. A plain Suspense boundary fixes hydration timing but bakes an empty hole into the frozen prelude, losing the body HTML from first paint. ## Core Features & Use Cases - Gated Suspense boundary: A ~40-line client component that keeps the full body HTML in the PPR prelude by using the content as its own fallback, then releases hydration on first idle at retry-lane priority. - Measured main-thread relief: Cuts the worst main-thread task from 2543ms to 386ms and total blocked time from 2705ms to 554ms on a production storefront homepage. - Sync-update trap guidance: Documents why post-hydration state syncs (basket, auth from storage) must be wrapped in startTransition to avoid force-hydrating the boundary synchronously. - Use Case: A content-heavy e-commerce homepage paints instantly from a cached shell but ignores clicks for seconds; wrap the page body in DeferredHydration so the header and nav hydrate immediately while the body hydrates after first idle. ## Quick Start Copy the DeferredHydration component into your app and wrap the heavy page body subtree with it while keeping the interactive chrome outside the boundary.
