awssdk_scoped_multidownload_s3.fsi

let s3List i = task {
  return [| $"foo%d{i}"; $"bar{i}"; $"baz{i}" |]
}

let s3Download k = task {
  return $"data%s{k}"
}

let inline flip f x y = f y x  // from FSharpPlus

let foo() = async {
  let! arrOfSetOfKeys = Async.Parallel <| seq {
      for d = 20230501 to 20230503 do
        yield async {
          let! keysList = s3List d |> Async.AwaitTask
          return Set.ofArray keysList
        }
  }
  let allKeys = Set.unionMany arrOfSetOfKeys
  let dlJobs = flip Seq.map allKeys <| fun k -> async {
    let! data = s3Download k |> Async.AwaitTask
    printfn $"data downloaded: %s{data}"
    return k
  }
  let limitParallelism = 3
  return! Async.Parallel(dlJobs, limitParallelism)
}

let bar() = let f = foo() |> Async.RunSynchronously
            printfn "%A" f

bar()