How can i send binary websocket message?

I’m trying to figure out how to send a websocket message as type binary.
The site i am testing has a messagepack encoding and every message to the websocket sent is binary
I can encode json to messagepack but i can’t send it using the websocket send block.

Also is there any way for me to add a origin header into the websocket connect request?
I am currently using an external application to modify the headers before sending to include an origin header.

Please create an issue on github and I will see if I can easily add this