export interface WsServer {
    broadcast: (json: string) => void;
    close: () => void;
    port: number;
}
export interface CreateWsServerOptions {
    getSceneJson: () => string;
    onClientMessage?: (json: string) => void;
}
/**
 * Creates a WebSocket server that broadcasts scene JSON to all connected clients.
 * On new connection, immediately sends the current scene state via getSceneJson().
 * If onClientMessage is provided, incoming messages from clients are passed to it.
 */
export declare function createWsServer(port: number, options: CreateWsServerOptions | (() => string)): WsServer;