title: How to use the Fetch API with TLS certificate?
body: <p>In the context of a service worker running in background and triggered by a <code>push</code> event, with Chrome (Android) not being launched, I'm trying to send an HTTP request with a TLS client certificate using the <code>fetch</code> API.</p>
  
  <p>When Chrome is launched the request succeeds, the TLS certificate already having been sent to the server. But the request fails in the case described above with the following error: <code>"failed to load resource: net::ERR_SSL_CLIENT_AUTH_CERT_NEEDED"</code>.</p>
  
  <p>I've tried using the <code>Request</code> options <code>{credentials: 'include'}</code> and <code>{ credentials: 'origin' }</code> but unsuccessfully.</p>
  
  <p>What is the proper way of using the fetch API with a TLS client certificate ?</p>