public Builder addDefaultXModule(final boolean includeDefaultXModule) {
            this.includeDefaultXModule = includeDefaultXModule;
            return this;
        }
Supply a default extension module of V2_0, V3_0 and V4_0 for serialization/deserialization.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/graphson/GraphSONMapper.java