F# - helper functions to Start and Wait for a plain Task (not Task<T>)

gistfile1.fs

open System.Threading.Tasks

[<AutoOpen>]
module Async =
    let inline awaitPlainTask (task: Task) = 
        // rethrow exception from preceding task if it fauled
        let continuation (t : Task) : unit =
            match t.IsFaulted with
            | true -> raise t.Exception
            | arg -> ()
        task.ContinueWith continuation |> Async.AwaitTask

    let inline startAsPlainTask (work : Async<unit>) = Task.Factory.StartNew(fun () -> work |> Async.RunSynchronously)

/// Usage
> let sleepy = async {
    do! Async.Sleep(5000) // sleep for 5 seconds
    printfn "awake"
  };;

val sleepy : Async<unit>

sleepy |> Async.startAsPlainTask;;
val it : Task = System.Threading.Tasks.Task {AsyncState = null;
                                             CreationOptions = None;
                                             Exception = null;
                                             Id = 2;
                                             IsCanceled = false;
                                             IsCompleted = false;
                                             IsFaulted = false;
                                             Status = Running;}
// 5 seconds later
> awake

> let sleepy2 = async {
    do! sleepy |> Async.startAsPlainTask |> Async.awaitPlainTask
    printfn "feeling sleepy again..."
  };;

val sleepy2 : Async<unit>

> sleepy2 |> Async.Start;;
val it : unit = ()

// 5 seconds later..

> awake
feeling sleepy again...