const { serve, upgradeHttp } = Deno; const u8 = Deno.core.encode("HTTP/1.1 101 Switching Protocols\r\n\r\n"); async function handler(req) { const [conn, _firstPacket] = upgradeHttp(req); await conn.write(u8); await conn.close(); } serve(handler, { hostname: "127.0.0.1", port: 9000, });