import { IPubSub } from './types';
export declare class WsJsonRpc implements IPubSub {
    readonly url: string;
    private _queue;
    private _ws;
    private _msgCount;
    constructor(url: string);
    exec(topic: string, message: any): Promise<any>;
    onMessage(handler: (topic: string, message: any) => void): {
        off: () => void;
    };
    private _connect;
    private _send;
}