title: WF4: Bookmark with NonBlocking option
body: <p>Has anyone used CreateBookmark() with BookmarkOptions.NonBlocking?
  I'm trying to use it with MultipleResume option but seems I cannot even resume.</p>
  
  <h2>Bookmark activity:</h2>
  
  <pre><code>    public InArgument&lt;string&gt; BookmarkName { get; set; }
      public InArgument&lt;BookmarkOptions&gt; BookmarkOptions { get; set; }
  
      protected override void Execute(NativeActivityContext context)
      {
          var options = BookmarkOptions.Get(context);
          context.CreateBookmark(BookmarkName.Get(context),
                                            ReadCompleteCallback,options);
      }
  </code></pre>
  
  <hr>
  
  <p>Test Code:</p>
  
  <hr>
  
  <pre><code> [TestMethod]
      public void TestMethod1()
      {
          InitWorkflow();
          wfat = WorkflowApplicationTest.Create(sm);
          wfat.TestActivity();
          Assert.IsTrue(wfat.WaitForIdleEvent());
          var res = wfat.TestWorkflowApplication.ResumeBookmark("First", "data");
          Assert.IsTrue(res == BookmarkResumptionResult.Success, "Resumption fail with result:" + res);
          Assert.IsTrue(wfat.Bookmarks.Contains("First"), "No first bkmk");
  
      }
  
  
      private void InitWorkflow()
      {
  
          sm = new StateMachine()
          {
              States = 
               {        //First state with non blocking bookmark             
                   new State(){
                        DisplayName = "First",Entry = new BookmarkActivity(){BookmarkName = "First",BookmarkOptions =
                                  BookmarkOptions.NonBlocking | BookmarkOptions.MultipleResume},
                        Transitions = 
                        {
                              new Transition(){ }
                       }
                   },    //Second state with blocking bookmark
                   new State(){
                       DisplayName = "Second",Entry =  new BookmarkActivity(){BookmarkName = "Second",BookmarkOptions =
                                  BookmarkOptions.None},
                       Transitions = 
                       {
                           new Transition(){ }
                       }
                   },
                   new State(){
                       DisplayName = "End",
                      IsFinal = true
                   }
               }
          };
          sm.InitialState = sm.States[0];
          sm.InitialState.Transitions[0].To = sm.States[1];
          sm.States[1].Transitions[0].To = sm.States[2];
      }
  </code></pre>
  
  <hr>
  
  <p>Result of ResumeBookmark in above test code is 'NotFound'</p>
  
  <p>I would appreciate any working code that demonstrates NonBlocking option.</p>