title: Google Tag manager: get the amount of time (minutes/seconds) it takes to complete progress
body: <p>I have an issue with tracking the completion of a progress within a web application. I want to track the amount of time it take for a user to finish a process (let's say he fills in an form, get's a confirmation and accepts the term/confirmation).
  The process takes place in three different pages.</p>
  
  <p>These are the three pseudo pages:</p>
  
  <pre><code>Page 1: Form
  Page 2: Confirmation
  Virtual pageview: Registration completed 
  </code></pre>
  
  <p>The Virtual pageview is being made when the user has pressed the submit button and there are no errors on the screen.</p>
  
  <p>What I would like to know now is:</p>
  
  <ul>
  <li>How to track the amount of time (seconds/minutes) it took the user to complete the registration? (in GTM)</li>
  </ul>