@Override
    public void write(final Kryo kryo, final Output output, final Tuple2<A, B> tuple2) {
        kryo.writeClassAndObject(output, tuple2._1());
        kryo.writeClassAndObject(output, tuple2._2());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
spark-gremlin/src/main/java/org/apache/tinkerpop/gremlin/spark/structure/io/gryo/Tuple2Serializer.java