code: public List<Object> getSubscribers(final Class<?> eventType, final String eventId) {
          final List<Object> eventSubs = new ArrayList<>();
  
          synchronized (registeredSubMap) {
              for (Map.Entry<Object, List<SubIdentifier>> entry : registeredSubMap.entrySet()) {
                  for (SubIdentifier sub : entry.getValue()) {
                      if (sub.isMyEvent(eventType, eventId)) {
                          eventSubs.add(entry.getKey());
  
                          break;
                      }
                  }
              }
          }
  
          return eventSubs;
      }
docs: Returns the subscriber which is registered with specified <code>eventType</code>(or its sub types) and <code>eventId</code>.
  
  @param eventType
  @param eventId
  @return