docs: @SuppressWarnings("unchecked")
      private static void pinStateChangeCallback(int pin, boolean state) {
  
          Vector<GpioInterruptListener> listenersClone;
          listenersClone = (Vector<GpioInterruptListener>) listeners.clone();
  
          for (int i = 0; i < listenersClone.size(); i++) {
              GpioInterruptListener listener = listenersClone.elementAt(i);
              if(listener != null) {
                  GpioInterruptEvent event = new GpioInterruptEvent(listener, pin, state);
                  listener.pinStateChange(event);
              }
          }
  
          //System.out.println("GPIO PIN [" + pin + "] = " + state);
      }