@Override
    public Map<String, Map<String, Long>> getQueueSizes() {
        Map<String, Map<String, Long>> queues = new HashMap<>();
        eventToQueueMap.forEach(
                (key, value) -> {
                    Map<String, Long> size = new HashMap<>();
                    size.put(value.getName(), value.size());
                    queues.put(key, size);
                });
        return queues;
    }
@return Returns a map of queues which are active. Key is event name and value is queue URI
core/src/main/java/com/netflix/conductor/core/events/DefaultEventQueueManager.java