@Override
            public void writeTo(Output output, Foo message) throws IOException
            {
                // 10 is an unknown field
                output.writeObject(10, baz, Baz.getSchema(), false);
                super.writeTo(output, message);
            }
Deserializes from the byte array and data is merged/saved to the message.
protostuff-core/src/test/java/io/protostuff/SerDeserTest.java