unwrap seq of asyncs into async seq

unwrap.fs

let! results = todo |> Seq.map (fun (name, param, sql) -> (name, db.ExecuteAsync conn param sql))
                    |> Seq.fold (fun (asyncAcc:Async<seq<string*Result<int>>>) (name,asyncTask) -> async{
                                                    let! acc = asyncAcc
                                                    let! taskRes = asyncTask
                                                    return seq {yield! acc; yield (name, taskRes)} 
                                                }) (async {return Seq.empty})