llows:</p>

<ul>
<li><strong>buffer:</strong> The amount of time (in ms) to buffer updates before
allowing another push to the undo stack. Defaults to <code>1000</code>.</li>
<li><strong>synchronize:</strong> A callback that is called after undos and redos,
allowing you to update data or displays. Alternatively see the
<code>on</code> and <code>off</code> methods for binding to events instead.</li>
<li><strong>synchronizeOnUpdate:</strong> Whether or not to call the <code>synchronize</code>
method when <cod