How to decode an encoded HttpWebResponse?

I have this piece of code to fetch a Page HTML from an URL, however the response content looks encoded.

Code:

HttpWebRequest xhr = (HttpWebRequest) WebRequest.Create(new Uri("https://www.youtube.com/watch?v=somevideoid"));
xhr.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
//xhr.CookieContainer = request.Account.CookieContainer;
xhr.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
xhr.Headers["Accept-Encoding"] = "gzip, deflate, br";
xhr.Headers["Accept-Language"] = "en-US,en;q=0.5";
xhr.Headers["Upgrade-Insecure-Requests"] = "1";
xhr.KeepAlive = true;
xhr.UserAgent = "Mozilla/4.0 (compatible; MSIE 9.0; Windows NT 6.1)";
xhr.Host = "www.youtube.com";
xhr.Referer = "https://www.youtube.com/watch?v=6aCpYxzRkf4";
var response = xhr.GetResponse();
string html;
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
    html = reader.ReadToEnd();
}

These are the response headers:

X-XSS-Protection: 1; mode=block; report=https://www.google.com/appserve/security-bugs/log/youtube
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
Strict-Transport-Security: max-age=31536000
Content-Encoding: br
Transfer-Encoding: chunked
Alt-Svc: quic=":443"; ma=2592000; v="44,43,39,35"
Cache-Control: no-cache
Content-Type: text/html; charset=utf-8
Date: Sat, 24 Nov 2018 11:30:38 GMT
Expires: Tue, 27 Apr 1971 19:44:06 EST
P3P: CP="This is not a P3P policy! See http://support.google.com/accounts/answer/151657?hl=it for more info."
Set-Cookie: PREF=f1=50000000&al=it; path=/; domain=.youtube.com; expires=Thu, 25-Jul-2019 23:23:38 GMT
Server: YouTube Frontend Proxy

The response generated by the server is in br encoding and I need to decode it. support for br encoding is not included in default system compression packages and you will have to install the Brotli.net nuget package.

I added this in my code to cover the 3 main encoding types gzip, br and defalte

HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
Stream responseStream = response.GetResponseStream();

if (response.ContentEncoding.ToLower().Contains("gzip"))
    responseStream = new GZipStream(responseStream, CompressionMode.Decompress);
else if (response.ContentEncoding.ToLower().Contains("deflate"))
    responseStream = new DeflateStream(responseStream, CompressionMode.Decompress);
else if (response.ContentEncoding.ToLower().Contains("br"))
    responseStream = new BrotliStream(responseStream, CompressionMode.Decompress);