import type { Awaitable } from "./Awaitable";
/**
 * Assume Stream content is ordered plain json object, (class is not supported)
 * And new element always insert into head
 *
 * Only emit unmet contents
 *
 * Once flow done, cache latest contents in windowSize, and skip from cached content next time
 *
 *
 */
export declare function cacheSkips<T>(store: {
    has?: (key: string) => Awaitable<boolean>;
    get: (key: string) => Awaitable<T[] | undefined>;
    set: (key: string, chunks: T[]) => Awaitable<any>;
}, _options?: string | {
    /**
     * Key could step name,
     * or defaults to `new Error().stack` if you r lazy enough
     */
    key?: string;
    /** defaults to 1, incase first n header may modify by others you could set it as 2 */
    windowSize?: number;
}): TransformStream<any, any>;