let workerScript = `self.onmessage = async function(event)
{
	let {url, options} = event.data;
	let res = await fetch(url, options);
	if (res.ok)
	{
		self.postMessage({
			ok: res.ok,
			url: res.url,
			status: res.status,
			headers: JSON.stringify([...res.headers]),
			redirected: res.redirected,
			body: res.body
		}, [res.body])
	} else self.postMessage({ok: res.ok, status: res.status})
}`;
let workerBlob = new Blob([workerScript], { type: 'application/javascript' });
fetcher._worker = new Worker(URL.createObjectURL(workerBlob));

fetcher._worker.onmessage = (event) =>
{
	if (event.data.ok)
	{
		fetcher._state = 1;
		fetcher._bytes = 0;
		fetcher._reader = event.data.body.getReader();

		let final_url = null;
		if (event.data.redirected) final_url = event.data.url;
		libgpac._fetcher_set_reply(fetcher.sess, event.data.status, final_url);

		let headers = JSON.parse(event.data.headers);
		headers.forEach(([value, key]) => {
			libgpac._fetcher_set_header(fetcher.sess, key, value);
		});
		libgpac._fetcher_set_header(fetcher.sess, 0, 0);
	}
	else
	{
		libgpac._fetcher_set_reply(fetcher.sess, event.data.status, null);
		do_log_err('fetcher for ' + url + ' failed ' + event.data.status);
		fetcher._state = 3;
	}
};

fetcher._state = 0;
fetcher._worker.postMessage({url, options}, [...(options.body ? [options.body] : [])]);
return ret;