import { ComapreOptions } from 'api-smart-diff';
import { MergedDocument } from '../types';
export declare class DiffWorkerManager {
    private worker;
    private pendingRequests;
    private nextId;
    private _useFallback;
    constructor(workerUrl?: string);
    /**
     * Merge before/after specs. Uses worker if available, otherwise falls back to sync.
     */
    merge(before: unknown, after: unknown, options?: ComapreOptions): Promise<MergedDocument>;
    /**
     * Terminate the worker and reject all pending requests.
     */
    destroy(): void;
}