private DefaultTraversalMetrics getTraversalMetricsFromSideEffects() {
        return (DefaultTraversalMetrics) this.getTraversal().getSideEffects().get(this.sideEffectKey);
    }
@author Bob Briody (http://bobbriody.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/sideEffect/ProfileSideEffectStep.java