private Set<Consumer<EventService.Event>> getMatchingSubscriptionsCallbacks(String eventLabel) {
        Set<Consumer<EventService.Event>> matchSet = new HashSet<Consumer<EventService.Event>>();
        String labelExplorer = "";
        synchronized (subscriptionsMap) {
            for(String scope: eventLabel.split(EVENT_SCOPE_SEPARATOR)) {
                labelExplorer += (labelExplorer.length()>0 ? EVENT_SCOPE_SEPARATOR : "") + scope;
                if(subscriptionsMap.containsKey(labelExplorer)) {
                    matchSet.addAll(
                            subscriptionsMap.get(labelExplorer).stream()
                            .map(s -> s.getConsumer())
                            .collect(Collectors.toCollection(HashSet::new)));
                }
            }
        }
        return matchSet;
    }
Gather all unique callbacks to call for an event dispatch
@param eventLabel The qualifier of the event whose listeners should be looked-up
@return A set of Consumers matching the label
src/main/java/com/kodedu/service/impl/EventServiceImpl.java