ait fetchText(&quot;https://altsvc.arthuredelstein.net:4433/protocol&quot;);
      console.log(&quot;after set:&quot;, responseText);
    }

read: async () =&gt; {
      const protocol = await fetchText(&quot;https://altsvc.arthuredelstein.net:4433/protocol&quot;);
      if ((new URL(location)).searchParams.get(&quot;thirdparty&quot;) === &quot;same&quot;) {
        if (protocol !== &quot;h3&quot;) {
          throw new Error(&quot;Unsupported&quot;);
        }
      }
      return protocol;
    }

result, 