title: can't override OnBeginDialogAsync in f# using TaskBulder.fs
body: <p>The f# code below fails to compile with the error: The member or object constructor <code>OnBeginDialogAsync</code> is not accessible. Private members may only be accessed from within the declaring type. Protected members may only be accessed from an extending type and cannot be accessed from inner lambda expressions.</p>
  
  <pre><code>type BaseDialog ( dialogId ) =
      inherit ComponentDialog( dialogId )
  
      override self.OnBeginDialogAsync(innerDc: DialogContext, options: obj, cancellationToken : CancellationToken) : Task&lt;DialogTurnResult&gt; =
          task{
              return! base.OnBeginDialogAsync(innerDc, options, cancellationToken )
          }
  </code></pre>
  
  <p>This uses task{} from <a href="https://github.com/rspeele/TaskBuilder.fs" rel="nofollow noreferrer">https://github.com/rspeele/TaskBuilder.fs</a></p>
  
  <p>Any way to invoke the base member from the override?</p>