I lack the required reputation to comment, so sorry about this.
I've discovered that I get a non-error response when I send the following:
{
"msg": "unsub",
"id": this._generateCallID(),
"name": "stream-room-messages",
"params":[
roomID,
true
]
}
This gives the following response:
{msg: "nosub", id: "ev5553ewl"}
I feel like I may be in the correct ballpark, but with the wrong ID or parameters. I'll keep you updated.
UPDATE:
I did some digging and found this in an issue:
{"msg": "unsub", "id": "subscriptionId"}
To unsubscribe from a channel, you simply provide your subscriptionID. The subscription ID being whatever ID you assigned to it when you made the subscription call initially.
I can confirm this method is working for my use-case.