getTimeElapsed in Swift with NSTimer
<p>I'm a beginner in Swift and I'm facing a problem.</p>

<p>I want to create a class that contains a timer and a button
Everytime the button is tapped I have to restart the timer, if the time elapsed between the timer starts and the button is tapped is greater (or equal) to 400 milliseconds, I have to call the function in the selector.</p>

<p>But there isn't a "GetTimeElapsed()" method in swift and I don't know how to do it.
If you have some clue/tutorials it could be cool !</p>

<p>Thx guys</p>