send custom header to origin

let's say you want to send the bot score to the origin server to serve different content. this will fetch the request and add a x-botscore header

addEventListener("fetch", (event) => {
  event.respondWith(
    handleRequest(event.request).catch(
      (err) => new Response(err.stack, { status: 500 })
    )
  );
});

async function handleRequest(request) {
  const cf = request.cf  
  request = new Request(request)
  request.headers.append("x-botscore", cf.botManagement.score)
  return fetch(request)
}