import { type Subscription } from "../teardown-manager.js";
import { Event, type Listener } from "./shared.js";
/**
 * AsyncEvent class to manage asynchronous events.
 * @template T
 * @template TReturnType
 * @extends {Event<T, TReturnType | PromiseLike<TReturnType>>}
 */
export declare class AsyncEvent<T extends unknown[] = unknown[], TReturnType = void> extends Event<T, TReturnType | PromiseLike<TReturnType>> {
    /**
     * Creates an instance of AsyncEvent.
     * @param {number} [maxListeners=10] - The maximum number of listeners.
     * @param {(args: TReturnType[]) => TReturnType} combineReturnTypes - Function to combine return types.
     */
    constructor(maxListeners?: number, combineReturnTypes?: Event<T, TReturnType>['combineReturnTypes']);
    /**
     * Adds a listener to the asynchronous event.
     * @param {Listener<T, TReturnType | Promise<TReturnType>>} listener - The listener to add.
     * @param {{ once?: boolean }} [options] - The event options.
     * @returns {Subscription} - The subscription.
     */
    addListener(listener: Listener<T, TReturnType | PromiseLike<TReturnType>>, options?: {
        once?: boolean;
    }): Subscription;
    /**
     * Emits the asynchronous event.
     * @param {...T} args - The arguments to pass to the listeners.
     * @returns {Promise<TReturnType>} - The return value of the listeners.
     */
    emit(...args: T): Promise<TReturnType>;
}