code: public void unregister(Object eventListener) throws MangooEventBusException {
          Objects.requireNonNull(eventListener, Required.EVENT_LISTENER.toString());
          
          try {
              this.eventBus.unregister(eventListener);
          } catch (IllegalArgumentException e) {
              throw new MangooEventBusException(e);
          }
  
          if (this.listeners.get() > 0) {
              this.listeners.getAndDecrement();            
          }
      }
docs: Unregisters an event listener to the event bus
  
  @param eventListener The listener to unregister
  @throws MangooEventBusException when unregistering an event fails