@Override
        public <O extends OutputShim> void write(final KryoShim<?, O> kryo, final O output, final YearMonth monthDay) {
            output.writeInt(monthDay.getYear());
            output.writeInt(monthDay.getMonthValue());
        }
Serializer for the {@link YearMonth} class.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/gryo/JavaTimeSerializers.java