@Override
        public void addBarrier(final Object barrier) {
            this.barrier.addBarrier(barrier);
        }
A helper class which holds a {@link Barrier} and it's related {@link ProfileStep} so that the latter can have
its timer started and stopped appropriately.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/ProfilingAware.java