Fable Async

fable.fs

open System.Threading

let taskGrandchild(order: int) : Async<unit> =
    async {
        printfn $"Starting Grandchild({order})"

        let! ct = Async.CancellationToken
        printfn $"Cancellation token GrandChild({order}): {ct.GetHashCode()}"

       // use! c = Async.OnCancel(fun () -> printfn $"Cancelled Task Grandchild: {order}")

        while (true) do
            printfn $"Waiting Grandchild({order})"

            do! Async.Sleep(100)
    }

let taskChild() : Async<unit> =
    async {
        printfn "Starting Child"

        let! ct = Async.CancellationToken
        printfn $"Cancellation token child: {ct.GetHashCode()}"

        //use! c = Async.OnCancel(fun () -> printfn "Cancelled Task Child")

        while (true) do
            do! taskGrandchild(1)
            do! taskGrandchild(2)
    }

let task () : Async<unit> =
    async {
        printfn "Starting"

        let! ct = Async.CancellationToken
        printfn $"Cancellation token: {ct.GetHashCode()}"

        //use! c = Async.OnCancel(fun () -> printfn "Cancelled")

        do! taskChild()
    }

let cts = new CancellationTokenSource(1000)
let ct = cts.Token
printfn $"Cancellation token main: {ct.GetHashCode()}"
Async.StartWithContinuations(task (), ignore, ignore, ignore, cts.Token)