title: Preview Mail Notification in browser
body: <p>With Laravel, according <a href="https://laravel.com/docs/5.5/mail#previewing-mailables-in-the-browser" rel="noreferrer">to the documentation</a>, I can return a <code>Mailable</code> via a controller to display it in the browser. It helps to preview mails. </p>
  
  <p><strong>Is there a way to preview Mail Notifications in browser?</strong> </p>
  
  <p>I tried:</p>
  
  <pre><code>return (new MyNotification())-&gt;toMail($some_user);
  </code></pre>
  
  <p>But it does not work:</p>
  
  <blockquote>
    <p>The Response content must be a string or object implementing __toString(), "object" given.</p>
  </blockquote>