export interface TurnHeartbeatOptions {
    /** The wire mount the turn was posted to (e.g. `https://host/api/vendo`). */
    baseUrl: string;
    /** Extra headers for beat requests (the client's wire headers). */
    headers?: Record<string, string>;
    /** Beat cadence; the server's idle window is a small multiple of this. */
    intervalMs?: number;
    /** Injection seam for tests; defaults to the global fetch. */
    fetch?: typeof fetch;
}
export declare function withTurnHeartbeat(response: Response, options: TurnHeartbeatOptions): Response;