export declare type EventHeader = {
    app_id: string;
    node_id: string;
    event_name: string;
};
export declare type AppEvent = {
    header: string;
    data: string;
};
export declare type Topic = string;
export declare type Handler = (payload: string) => void | Promise<void>;
export declare type SubscriberToken = `_${Topic}_token_${number}_`;
export interface IPubSub {
    publish(topic: Topic, payload: string): void;
    subscribe(topic: Topic, handler: Handler): SubscriberToken;
    hasSubscribers(topic?: Topic): boolean;
    unSubsribeByTopic(topic: Topic): boolean;
    unSubsribeByToken(token: SubscriberToken): boolean;
    unSubsribeByHandler(hanlder: Handler): boolean;
    clearAllSubscriptions(): void;
}