How do I set a Header for a Response in Appwrite Functions?

  const payload = req.req?.bodyJson || req.req?.body || req.req?.bodyText || req.req?.bodyRaw;

  const { action, ...params } = payload;
  console.log("Action:", action);
  console.log("Params:", params.cors_origin);
  console.log(process.env.ACCESS_TOKEN);
  console.log(process.env.SECRET_KEY);

  try {
    let response;

    if (action === 'createUploadUrl') {
      console.log("Creating upload URL");

      // Create the upload URL with Mux API
      /*const upload = await mux.video.uploads.create({
        cors_origin: params.cors_origin, // '*' for testing; update for production
        new_asset_settings: {
          playback_policy: ['public'],
          video_quality: 'basic'
        }
      });*/

      const test = "Works123";
      const temp = { success: true, uploadUrl: test, uploadId: test };
      console.log("req.query.type:", req.query.type);
      res.setHeader('Content-Type', 'application/json');
      return res.json(temp);

    }
  } catch (error) {
    return { success: false, error: error.message };
  }
};```