<h1>
    CollectionView Notifications and Performance
</h1>
<p>
    The <b>CollectionView</b> class is highly optimized.
    It sorts, filters, groups, and paginates large data
    sets efficiently in virtually every situation.
</p>
<p>
    In some cases, you may be able to improve performance
    even more by using the <b>deferUpdate</b> method to
    suspend refreshes while performing batch operations.
</p>
<p>
    This is especially important when adding items to collections
    that are sorted, grouped, or filtered. Without deferred
    updates, each addition causes a refresh.
</p>
<p>
    For example, click the buttons below to add 1,000
    items to a <b>CollectionView</b> using three
    different methods:
</p>

<button id="btnAddNew" class="btn btn-default">
    addNew
</button>
<br>
<button id="btnPush" class="btn btn-default">
    push
</button>
<br>
<button id="btnPushDefer" class="btn btn-default">
    push + defer updates
</button>