Async Function Tasks() As Task
    Dim tasks(2) As Task
    tasks(0) = Task.Run(AddressOf Task1)
    tasks(1) = Task.Run(AddressOf Task2)
    tasks(2) = Task.Run(AddressOf Task3)
    Await Task.WhenAll(tasks)
    MsgBox("Alle Tasks wurden beendet.")
  End Function

  Private Async Function LeseDateiAsynchron() As Task
    Dim zeit = Date.Now
    Dim tasklist As New List(Of Task)
    tasklist.Add(Task.Run(AddressOf Leser1))
    tasklist.Add(Task.Run(AddressOf Leser2))
    tasklist.Add(Task.Run(AddressOf Leser3))
    tasklist.Add(Task.Run(AddressOf Leser4))
    While tasklist.Count > 0
      Dim tk = Await Task.WhenAny(tasklist)
      tasklist.Remove(tk)
      'Dim rg = Await tk '<- nur wenn auf einen Rückgabewert gewartet werden _
        soll.
      Me.ProgressBarFortschritt.Value += 20
      Me.LabelZeit.Text = String.Format("Zeit: {0:n1} Sek.", (Date.Now - _
        zeit).TotalSeconds)
    End While
    Me.ProgressBarFortschritt.Value = 100
  End Function

  Private Async Sub ButtonWeb_Click(sender As Object, e As EventArgs) Handles _
    ButtonWeb.Click
    Me.ButtonWeb.Enabled = False
    Dim inhalt = Await InhaltWebseite("...")
    '...
    Me.ButtonWeb.Enabled = True
  End Sub
 
  Private Async Function InhaltWebseite(url As String) As Task(Of String)
   Return Await New HttpClient().GetStringAsync(url)
  End Function