_onQueueStarted(event) {
        if (event === 'init') {
            this.lastInitStartTime = Date.now();
            this.finished = false;
        }
    }
@description The queue will notify us if the queue has started with an event.

The "init" event is basically the bootstrap event, which is the siganliser if url generation
is in progress or not.

@param {String} event
@private