@Override
    public boolean toData(Object o, DataOutput out) throws IOException {
      if (o instanceof DataSerializableImpl) {
        fail("toData() should not be invoked with a " + o.getClass().getName());
      }
      return false;
    }
Tests that an <code>Instantiator</code> is invoked at the appropriate times.
geode-core/src/test/java/org/apache/geode/internal/DataSerializableJUnitTest.java