title: Timer.scheduledTimer not firing
body: <p>I am trying to calculate the time it takes a vehicle to go between two checkpoints. I have setup the following timer to achieve this.</p>
  
  <pre><code>func startTimer() {
      if hasStarted == true &amp;&amp; timerStarted == false {
          print("Timing started!")
          gameTimer = Timer.scheduledTimer(timeInterval: 0.001, target: self, selector: (#selector(activeTiming)), userInfo: nil, repeats: true)
          timerStarted = true
      }
  }
  
  @objc func activeTiming() {
      print("Active timing block")
      if(hasFinished == false) {
          gameTime = gameTime + 0.001
          print("Add time succeeded")
      } else {
          gameTimer?.invalidate()
      }
  }
  </code></pre>
  
  <p>The expected output would be the following:</p>
  
  <pre><code>Timing started!
  Active timing block
  Add time succeeded
  Add time succeeded ... etc
  </code></pre>
  
  <p>The actual output:</p>
  
  <pre><code>Timing started!
  </code></pre>
  
  <p>So it would appear that the startTimer is properly being called but the timer is not firing the activeTiming block of code. Any suggestions would be extremely helpful. Thank you for your help in advance.</p>