Test work IProgress interface in fs

progress.fsx

open System.IO
open System.Net
open System.Text
open System

let httpAsync (progress : IProgress<string>) (url : string) = async {
    let req = System.Net.WebRequest.Create(url)
    use! resp = req.AsyncGetResponse()
    progress.Report(sprintf "%s AsyncGetResponse" url)
    use stream = resp.GetResponseStream()
    use reader = new StreamReader(stream, Encoding.GetEncoding(1251))
    return!  reader.ReadToEndAsync() |> Async.AwaitTask }

let println = printfn "%s"    
let progress = new Progress<string>(fun s -> println s)
(progress :> IProgress<string>).Report("test") //не работает
println "line" // работает

//let httpProgress = httpAsync (progress)