title: How to clear toast messages in primeng?
body: <p>I am using Angular8 and Primeng-8.1.1 version with Growl.</p>
  <p>When there are more than one toast messages, screen looks very unclear because of multiple toast messages. I want to remove all the previously opened toast messages. Right now, I am using the below code as per primeng documentation. But it is not clearing the old toast messages.</p>
  <pre><code>this.messageService.clear();
  this.messageService.add({
      severity: &quot;success&quot;,
      summary: &quot;Success Message&quot;,
      detail: &quot;Success Message&quot;
  });
  </code></pre>