import { Router } from 'express';
/**
 * Creates an instance of a message broker server.
 * Many message broker servers may be created, each bound to a different base url.
 * @param cacheLastMessage When true, subscribers will receive the last message upon subscrition.
 * @returns Returns an express Router for use within an express application.
 */
export declare function server(cacheLastMessage?: boolean): Router;