@FeatureDescriptor(name = FEATURE_PERSISTENCE)
            default boolean supportsPersistence() {
                return true;
            }
Determines if the {@code Graph} implementation supports persisting it's contents natively to disk.
This feature does not refer to every graph's ability to write to disk via the Gremlin IO packages
(.e.g. GraphML), unless the graph natively persists to disk via those options somehow.  For example,
TinkerGraph does not support this feature as it is a pure in-sideEffects graph.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/Graph.java