title: data of MotionActivity is only updated every 3 or 4 secs instead of 0.01 secs
body: <p>I've setup a Timer() to update every 0.01 seconds the data of MotionActivity, but it only updates every 3 to 4 seconds. Why?</p>
  
  <pre><code>        timer = Timer.scheduledTimer(timeInterval: 0.01, target: self, selector: #selector(ViewController.updateWatch), userInfo: nil, repeats: true)
  
  func updateWatch() {
      if CMMotionActivityManager.isActivityAvailable() {
          activtyManager.startActivityUpdates(to: OperationQueue.main, withHandler: { (data: CMMotionActivity!) in
              print(data)
              if data.stationary == false { some code } }) } else { print("error") }
  </code></pre>