Is it possible to unbind onclose handler in SignalR JS client?

[planty]

I am using the SignalR JS client with Azure SignalR Service (Serverless). I would like to be able to support multiple resources for resiliency (it would be nice if this was available as a standard feature!), so I provide my client with a SignalRConnectionInfo object for each resource. My client can then automatically switch to another resource if it encounters an error with the first one it tries.
When this happens, I want to reassign my HubConnection object with a new instance, but I'm worried that this might leak event handlers - I can call the off methods to unbind my own event handlers, but there is no equivalent for the onclose method.

I've included a simplified example of my setup and connection functions

private async setupConnection(connectionInfo: SignalrConnectionInfo) {
    const options = {
        accessTokenFactory: () => connectionInfo.accessToken
    };

    this.connection = new HubConnectionBuilder()
        .withUrl(connectionInfo.url, options)
        .build();

    this.connection.on('message', (data: any) => {
        // do stuff
    });

    this.connection.onclose(async (err) => {
        setTimeout(() => this.tryNextConnection(), 5000);
    });
}

private async connect() {
    try {
        await this.connection.start();
    } catch (err) {
        setTimeout(() => this.tryNextConnection(), 5000);
    }
}

The tryNextConnection method will call setupConnection with a different connectionInfo object and attempt a new connection to the 'next' resource. If there are no other connectionInfo objects to try, it will reuse the same details as before.

The more times a connection attempt fails, the more HubConnections it would create, which is why I'm concerned about leaking handlers. Looking at the C# client, I assume I would be able to unbind the closed handler using connection.Closed -= ... so is there any reason we couldn't do this in the JS client?

Also, are there any plans to support multiple serverless resources natively?