public GryoVersion getVersion() {
        return version;
    }
A {@link Mapper} implementation for Kryo. This implementation requires that all classes to be serialized by
Kryo are registered to it.
<p/>
{@link Graph} implementations providing an {@link IoRegistry} should register their custom classes and/or
serializers in one of three ways:
<p/>
<ol>
<li>Register just the custom class with a {@code null} {@link Serializer} implementation</li>
<li>Register the custom class with a {@link Serializer} implementation</li>
<li>
Register the custom class with a {@code Function<Kryo, Serializer>} for those cases where the
{@link Serializer} requires the {@link Kryo} instance to get constructed.
</li>
</ol>
<p/>
For example:
<pre>
{@code
public class MyGraphIoRegistry extends AbstractIoRegistry {
  public MyGraphIoRegistry() {
    register(GryoIo.class, MyGraphIdClass.class, new MyGraphIdSerializer());
  }
}
}
</pre>

@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/gryo/GryoMapper.java