@Override
    public TimeLimitStep<S> clone() {
        final TimeLimitStep<S> clone = (TimeLimitStep<S>) super.clone();
        clone.timedOut = new AtomicBoolean(this.timedOut.get());
        clone.startTime = new AtomicLong(this.startTime.get());
        return clone;
    }
@author Randall Barnhart (random pi)
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/TimeLimitStep.java