title: Measuring elapsed time in QML
body: <p>Let's consider the following example: we have a Qt Quick Controls <code>Button</code>. The user clicks it twice within 5 seconds. After pushing the <code>Button</code> for the first time, the QML <code>Timer</code> is running for these 5 seconds. We want to measure the time elapsed between two clicks, with a millisecond accuracy.</p>
  
  <p>Unfortunately, the QML <code>Timer</code> can't show us the elapsed time.</p>
  
  <p>As suggested on the BlackBerry forums, it would be possible to compare the dates. This isn't very handy, though, since the first click might occur on <code>31 Dec 2015, 23:59:55</code> and the second on <code>1 Jan 2016, 00:00:05</code> and the check would have to be complex. </p>
  
  <p>Is there any better  option?</p>