<para>The <seecref="M:Gtk.PrintOperation.UpdateCustomWidget"/> event utilizes this delegate:</para>
<para>Event data is passed via the <seecref="T:Gtk.UpdateCustomWidgetArgs"/> parameter.</para>
<para>To attach a <seecref="T:Gtk.UpdateCustomWidgetHandler"/> to an event, add the UpdateCustomWidgetHandler instance to the event. The methods referenced by the UpdateCustomWidgetHandler instance are invoked whenever the event is raised, until the UpdateCustomWidgetHandler is removed from the event.</para>