/**
 * Go through the elements of an iterable and return zero or more of them using
 * an async iterable.
 *
 * @param mapper the mapper function to run over the async iterable
 */
export declare function flatMap<TFrom, TTo>(mapper: (t: TFrom) => AsyncIterable<TTo>): (source: AsyncIterable<TFrom>) => AsyncGenerator<TTo, void, unknown>;