docs: public void register (int objectID, Object object) {
  		if (objectID == Integer.MAX_VALUE) throw new IllegalArgumentException("objectID cannot be Integer.MAX_VALUE.");
  		if (object == null) throw new IllegalArgumentException("object cannot be null.");
  		idToObject.put(objectID, object);
  		objectToID.put(object, objectID);
  		if (TRACE) trace("kryonet", "Object registered with ObjectSpace as " + objectID + ": " + object);
  	}