public default Supplier<TraverserSet<S>> getTraverserSetSupplier() {
            return TraverserSetSupplier.instance();
        }
Gets a generator that creates new {@link TraverserSet} instances for steps in the traversal. Providers may
override this default implementation to provider their own {@link TraverserSet}.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/Traversal.java