interface AggregationGroupComputerimport { type AggregationGroupComputer } from "https://dotland.deno.dev/x/pg_mem@2.6.13/interfaces-private.ts"; Type ParametersoptionalTRet = anyMethodsfeedItem(item: any): voidWhen iterating, this will be called for each item in this group finish(): TRet | nilFinish computation (sets aggregation on result)