import { AsyncSequence } from "../../sequency";
export declare class DistinctBy {
    /**
     * Returns a new sequence which discards all elements with duplicate items determined
     * by the given `selector`.
     *
     * @param {(item: T) => Promise<K> | K} selector
     * @returns {AsyncSequence<T>}
     */
    distinctBy<T, K>(this: AsyncSequence<T>, selector: (item: T) => Promise<K> | K): AsyncSequence<T>;
}