title: Postman multipart/form-data error: Missing start boundary
body: <p>I'm trying to hit my server's endpoint with a <code>multipart/form-data</code> request sent from Postman. I'm getting a <strong>400 Bad Request</strong> and the cause is:</p>
  
  <pre><code>org.jvnet.mimepull.MIMEParsingException: Missing start boundary.
  </code></pre>
  
  <p>How can I set the start boundary and how do I know what it should be?</p>
  
  <p><a href="https://i.stack.imgur.com/Gc9rI.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Gc9rI.png" alt="enter image description here"></a></p>