asyncScan: <A, B>(
fn: AsyncReducer<A, B>,
acc: B,
iter: Iterable<A, any, any> | AsyncIterable<A, any, any>,
) => AsyncGenerator<B> & <A, B>(
fn: AsyncReducer<A, B>,
acc: B,
) => (
iter: Iterable<A, any, any> | AsyncIterable<A, any, any>,
) => AsyncGenerator<B> = ...