title: Live Update the Number of Items
body: <p>I have a requirement where I need to live update the number of list items to Page's sub-header. I want use <code>sap.ui.base.EventProvider</code>, aggregation binding, or expression binding. Please walk me through as I have never used it before.</p>
  
  <p>If I delete a list item, the number of list item should live update.</p>