/**
 * Result of the `useLayerReady` hook.
 * Provides the `ready` promise, `loadsData` flag, and current `isLoading` state
 * for use in layer handles.
 */
export type LayerReadyResult = Readonly<{
    /** Resolves when initial data is available. Stable reference across renders. */
    ready: Promise<void>;
    /** Whether this layer fetches its own data (true when `loading` arg is provided). */
    loadsData: boolean;
    /** Current loading state. */
    isLoading: boolean;
}>;
/**
 * Shared hook that tracks initial data readiness for a layer.
 *
 * - `loading: undefined` -> not a data-loading layer; ready immediately.
 * - `loading: false` -> data-loading layer with data already available; ready immediately.
 * - `loading: true` -> data-loading layer still waiting; ready is a deferred promise
 *   that resolves on the first `true -> false` transition.
 *
 * Once resolved, the promise stays resolved. Subsequent `true -> false` cycles
 * do NOT re-pend -- this hook tracks *initial* readiness only.
 */
export declare const useLayerReady: (loading?: boolean) => LayerReadyResult;