code: public String registerDevice(String deviceId) throws ApiException, IOException {
          return registerDevice(new Device.Builder(projectId).id(deviceId).build());
      }
docs: Registers a device with the provided device ID. This call is <b>BLOCKING</b> and should not
  be called on UI threads.
  
  See {@link #registerDevice(Device)} for more details.
  
  @param deviceId The desired id for this device; if null, a random one is assigned.
  @return The new device id for this device.
  @throws ApiException Thrown if the iobeam client is not initialized or there are problems
  writing the device ID.
  @throws IOException  Thrown if network errors occur while trying to register.