title: Karate automatically sets Content-Type header
body: <p>Good day! In my negative test cases I have to PUT a request without Content-Type header in order to match desired 4xx status code. The problem is karate automatically sets an appropriate Content-Type.
  E.g. when I pass {} as request it sets application/json; charset=UTF-8
  when I pass '' as request it sets text/plain; charset=UTF-8</p>
  
  <p>The question is how can I send a PUT request without a Content-Type header?</p>