title: HTML vs Plain text as body in email
body: <p>When creating a <a href="http://swiftmailer.org/docs/messages.html"><code>Swift_Message</code></a> you can have both a plain text and an html version of the email. You set one as the body, and then you add the other one as a part.</p>
  
  <p>What is the difference if I set the HTML version as body and plain text as part, and the other way around?</p>
  
  <pre><code>$html_as_body = Swift_Message::newInstance()
      -&gt;setSubject($subject)
      -&gt;setBody($html, 'text/html')
      -&gt;addPart($plain, 'text/plain');
  
  $plain_as_body = Swift_Message::newInstance()
      -&gt;setSubject($subject)
      -&gt;setBody($plain, 'text/plain')
      -&gt;addPart($html, 'text/html');
  </code></pre>
  
  <p>And by difference, I mean what kind of difference will it have in email readers and such?</p>