title: Application in xamarin.mac that takes screenshots and system idle time
body: <p>Actually, I'm new to 'xamarin.mac' applications and I'm trying an application that takes screenshot frequently also captures system idle time on login.So far I've managed to capture screenshot but How to take system idle time? </p>
  
  <p>I've gone through 'NSEvents'.But I cannot figure it out how to implement those
  event against button click.</p>
  
  <p>I just want the system idle time count that starts on login.</p>