import { CallContextLike } from '@xh/hoist/core';
import type { FetchOptions } from '../FetchService';
/**
 * Post a JSON body, using `fetch({keepalive: true})` when the page is no longer visible so the
 * request can survive teardown (e.g. a flush as `XH.pageState` goes `hidden`/`frozen`/`terminated`).
 *
 * Keepalive bodies share a single browser-wide 64KB budget; if exceeded the request is never sent
 * and we retry once uncapped (without keepalive), which still completes while the page is alive (the
 * common `hidden` case). Real server errors are re-thrown, not re-posted.
 *
 * @internal
 */
export declare function terminationSafePostJson(opts: FetchOptions, ctx?: CallContextLike): Promise<any>;