/**
 * Park until a waiting `ctx.waitForUpdate` handler responds (via the resolver it
 * registered in `updateWaiters`) or the update times out. Resolves with the
 * handler's response value; rejects with {@link UpdateTimeoutError} when the
 * timeout elapses first. The `respond` callback is single-shot — a late second
 * response is ignored.
 */
export declare function waitForUpdateResponse(updateId: string, payload: unknown, timeout: number, updateWaiter: (request: unknown) => void): Promise<unknown>;