import { AsyncReducer } from "https://deno.land/x/rimbu@1.2.1/mod.ts";
const { Base } = AsyncReducer;
Parameters
flatMapFun: (value: I2, index: number) => MaybePromise<AsyncStreamSource<I>>
x/rimbu/mod.ts>AsyncReducer.Base#flatMapInput
import { AsyncReducer } from "https://deno.land/x/rimbu@1.2.1/mod.ts";
const { Base } = AsyncReducer;