display button toolbar on custom admin page

I’m working with Magento 2.3. I have a custom admin page which I made following this tutorial –

https://devdocs.magento.com/guides/v2.3/ext-best-practices/extension-coding/example-module-adminpage.html

I want to have a button toolbar on my page as is visible on all admin pages like this –

enter image description here

I have this code –

<type name="Vendor\Module\Block\ButtonToolbar">     <plugin name="buttonToolbarConvert" type="Vendor\Module\Plugin\Toolbar" disabled="false" /> </type> 

Toolbar.php –

public function beforeSetLayout( \Magento\Framework\View\Element\AbstractBlock $  context){     var_dump("set layout");     $  this->buttonList->add(             'mybutton',             ['label' => __('My Button'), 'onclick' => 'setLocation(window.location.href)', 'class' => 'reset'],             -1         ); } 

Shows ‘set layout’ but does not show the button.