import { AsyncReducer } from "https://deno.land/x/rimbu@1.1.0/stream/mod.ts";
const { Base } = AsyncReducer;
Parameters
mapFun: (value: I2, index: number) => MaybePromise<I>
import { AsyncReducer } from "https://deno.land/x/rimbu@1.1.0/stream/mod.ts";
const { Base } = AsyncReducer;