/**
 * Wait until the first paint has happened and the main thread has had an idle
 * moment, then run `callback` exactly once. Returns a cancel function.
 *
 * Fast path: `requestAnimationFrame` → `requestIdleCallback` (with a timeout
 * so a busy main thread cannot starve it). Two safety nets keep the callback
 * reliable: browsers without `requestIdleCallback` fall back to a macrotask,
 * and a bounded timer covers hidden tabs where `requestAnimationFrame` never
 * fires. Never runs during SSR — React effects do not run on the server, and
 * the scheduler is a no-op without a `window`.
 */
export type ScheduleAfterPaintCancel = () => void;
export declare function scheduleAfterPaint(callback: () => void): ScheduleAfterPaintCancel;
export declare function useAfterPaint(): boolean;
/**
 * `scheduleAfterPaint`, but never before the page is `STARTUP_SETTLE_MS` old.
 * Later in the page's life it is `scheduleAfterPaint` unchanged.
 */
export declare function scheduleAfterStartup(callback: () => void): ScheduleAfterPaintCancel;
export declare function useAfterStartup(): boolean;