title: Can you set the Host header using fetch API
body: <p>I have a reverse proxy server, which redirects you to different services depending on the Host header.
  However when making requests to this server using a browser, the <code>Host</code> is always set to the domain name in the URL. I tried:</p>
  
  <pre><code>fetch("http://foo.com", {"headers":{"Host":"bar.foo.com"}})
  </code></pre>
  
  <p>But it doesn't work</p>