FSharp recursive async fuction [Leaking] + Closure representation

gistfile1.fs

[<EntryPoint>]
let main argv = 
    let rec loop () = async {
        do! Async.Sleep 10
        return! loop ()
        return! loop () }
    Async.Start <| loop ()
    System.Console.ReadLine() |> ignore
    0
    
(* compled representations of loop
loop@6-3
    loop: Microsoft.FSharp.Core.FSharpFunc<Microsoft.FSharp.Core.Unit,Microsoft.FSharp.Control.FSharpAsync<Microsoft.FSharp.Core.Unit>>
    builder@: Microsoft.FSharp.Control.FSharpAsyncBuilder

loop@5-2
    loop: Microsoft.FSharp.Core.FSharpFunc<Microsoft.FSharp.Core.Unit,Microsoft.FSharp.Control.FSharpAsync<Microsoft.FSharp.Core.Unit>>
    builder@: Microsoft.FSharp.Control.FSharpAsyncBuilder

loop@4-1
    loop: Microsoft.FSharp.Core.FSharpFunc<Microsoft.FSharp.Core.Unit,Microsoft.FSharp.Control.FSharpAsync<Microsoft.FSharp.Core.Unit>>
    builder@: Microsoft.FSharp.Control.FSharpAsyncBuilder
*)