/**
 * Defines the signature for the Callback that an EventSubscription should have.
 *
 * @param eventPayload Optional: The payload received with the event.
 * @param eventName    Optional: The name of the received event.
 */
export type EventReceivedCallback = (eventPayload?: any, eventName?: string) => void | Promise<void>;
/**
 * Contains information about a subscription on the EventAggregator.
 * External services can use this information to manage their own subscriptions.
 */
export type Subscription = {
    /**
     * The Id under which the EventAggregator has stored the Subscription.
     */
    readonly id: string;
    /**
     * The name of the event for which the Subscription was created.
     */
    readonly eventName: string;
    /**
     * If set to true, the Subscription will be destroyed after first receiving
     * the event.
     */
    readonly onlyReceiveOnce: boolean;
};
declare function subscribe(eventName: string, callback: EventReceivedCallback): Subscription;
declare function subscribeOnce(eventName: string, callback: EventReceivedCallback): Subscription;
declare function publish(eventName: string, payload?: any, onAcknowledgement?: () => void, eventId?: string): void;
declare function acknowledgeEvent(eventId: string): void;
declare function unsubscribe(subscription: Subscription): void;
declare function clear(): void;
export declare const EventAggregator: {
    acknowledgeEvent: typeof acknowledgeEvent;
    subscribe: typeof subscribe;
    subscribeOnce: typeof subscribeOnce;
    publish: typeof publish;
    unsubscribe: typeof unsubscribe;
    /**
     * Clears all subscriptions currently registered on the Event Aggregator.
     *
     * CAUTION - Use this only for cleanup procedures during shutdown. DO NOT use this during normal operations!
     */
    clear_UNSAFE: typeof clear;
};
export default EventAggregator;