import { AsyncIterableX } from '../../asynciterable/asynciterablex';
/**
 * @ignore
 */
export declare function maxByProto<TSource, TKey>(this: AsyncIterableX<TSource>, keySelector: (x: TSource) => TKey | Promise<TKey>, comparer?: (x: TKey, y: TKey) => number | Promise<number>): AsyncIterableX<TSource>;
declare module '../../asynciterable/asynciterablex' {
    interface AsyncIterableX<T> {
        maxBy: typeof maxByProto;
    }
}