title: Google Analytics: Time on "Screen" for fragment
body: <p>We want to track via Google Analytics the amount of time the user spends on each fragment of one activity.</p>
  
  <p>Just to be clear, we have one activity and many fragments that belongs to the same activity.</p>
  
  <p>I need to know how much time the user spent in each of those fragments and send it as "Time on screen". How can I do that? </p>