rntype"><a href="dart-core/int-class.html">int</a></span>
                  <span class="name ">tick</span>
          
</section>
        
                <section class="desc markdown">
          <p>The number of durations preceding the most recent timer event.</p>
<p>The value starts at zero and is incremented each time a timer event
occurs, so each callback will see a larger value than the previous one.</p>
<p>If a periodic timer with a non-zero duration is delayed too much,
so more than one tick should 