Hi I have simple service worker, but my Range header is not being send even thought i can log it on request object.

self.addEventListener('fetch', async function(event) { if (event.request.headers.get("range")) { const response = await fetch(event.request.clone()); return event.respondWith(this.getPartialResponse(event.request, response)); } return event.respondWith(fetch(event.request)); } async getPartialResponse(req, res) { const pos = Number(/^bytes\=(\d+)\-$/g.exec(req.headers.get("range"))[1]); const ab = await res.arrayBuffer(); const headers = new Headers(res.headers); headers.append("Content-Range", `bytes ${pos}-${ab.byteLength - 1}/${ab.byteLength}`); headers.append("Content-Length", ab.byteLength - pos + 1); return new Response(ab.slice(pos), { status: 206, statusText: "Partial Content", headers }); }