C# Send raw byte array to website

I need to send to a website or webserver a POST request, but it must be in its raw form (as seen in fiddler hex view) and then get the response. It is a byte array that I already have (and is always the same) with the "POST ...." with headers, cookies, values, everything set up.

I expect a function like SendRawBytes(url, bytes); that sends only the "bytes" variable.

I've already tried WebClient.UploadData(url, data) but it adds the POST, HOST, Content-Length and Expect to the request.

Anything would be of great help!

Thank you in advance.