@Override
      public void beforeCreate2(EntryEvent event) throws CacheWriterException {

        Object[] array = (Object[]) event.getCallbackArgument();
        assertEquals(two, array[0]);
      }
Tests that a local writer receives a modified version of the callback argument on a create.
geode-core/src/distributedTest/java/org/apache/geode/cache30/LocalRegionDUnitTest.java