@Override
    public void reset() {
        super.reset();
        this.head = null;
        this.done = false;
        this.iterator = EmptyIterator.instance();
    }
Gets the ids associated with this step as literal values rather than {@link GValue} objects.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/GraphStep.java