docs: public List<IoDevice> getUsedIoDevices()
      {
          final ArrayList<IoDevice> used = new ArrayList<>();
          synchronized (mIODevices)
          {
              for (IoDevice d : mIODevices)
              {
                  if (isDeviceActive(d))
                  {
                      used.add(d);
                  }
              }
          }
          return used;
      }