import { AsyncIterableX } from '../asynciterable';
/**
 * Projects each element of a sequence to a potentially async iterable and flattens the
 * resulting sequences into one sequence.
 * @param {Iterable<T | Promise<T>> | AsyncIterable<T>} source Source sequence
 * @param {function:(value: T): Iterable<R | Promise<R>> | AsyncIterable<R>} selector A transform function to apply to each element.
 * @param {Object} [thisArg] An optional "this" binding for the selector function.
 * @returns {AsyncIterable<R>} An async iterable whose elements are the result of invoking the one-to-many
 * transform function on each element of the input sequence.
 */
export declare function flatMapAsync<TSource, TResult>(source: Iterable<TSource | PromiseLike<TSource>> | AsyncIterable<TSource>, selector: (value: TSource) => Iterable<TResult | PromiseLike<TResult>> | AsyncIterable<TResult>, thisArg?: any): AsyncIterableX<TResult>;