/**
 * Track whether a new version of the site has been downloaded by the service
 * worker and is waiting to take over.
 *
 * A waiting worker means every asset of the new version is already cached, so
 * installing it is just `skipWaiting` followed by a reload. The reload is
 * triggered from the worker's `activated` state change rather than immediately,
 * so the page never reloads into the old version.
 *
 * Replaces the DOM based `[data-update-worker]` wiring in the site bundle, which
 * only works for markup that exists when the page loads.
 */
export declare function useServiceWorkerUpdate(): {
    isUpdateAvailable: boolean;
    installUpdate: () => void;
};