servePing() {
        if (this.uibRouter === undefined) throw new Error('this.uibRouter is undefined')

        this.uibRouter.get('/ping', (req, res) => {
            res.status(204).end()
        })
        this.routers.user.push( { name: 'Ping', path: `${this.uib.httpRoot}/uibuilder/ping`, desc: 'Ping/keep-alive endpoint, returns 201', type: 'Endpoint', } )
    }
Add the ping endpoint to /uibuilder/ping
This just returns a 201 (No Content) response and can be used for a keepalive process from the client.