@Override
    public TailGlobalStep<S> clone() {
        final TailGlobalStep<S> clone = (TailGlobalStep<S>) super.clone();
        clone.tail = new ArrayDeque<>(this.limit.get().intValue());
        clone.tailBulk = 0L;
        return clone;
    }
@author Matt Frantz (http://github.com/mhfrantz)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/TailGlobalStep.java