public void finish(final long bulk) {
        stop();
        incrementCount(TraversalMetrics.TRAVERSER_COUNT_ID, 1);
        incrementCount(TraversalMetrics.ELEMENT_COUNT_ID, bulk);
    }
Gets a copy of the metrics that is immutable. Once this clone is made, the {@link MutableMetrics} can no
longer be modified themselves. This prevents custom steps that implement {@link Profiling} from adding to
the metrics after the traversal is complete.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/util/MutableMetrics.java