@Override
    public MemoryComputeKey<TraverserSet<S>> getMemoryComputeKey() {
        if (null == this.multiComparator) this.multiComparator = this.createMultiComparator();
        return MemoryComputeKey.of(this.getId(), new OrderBiOperator<>(this.limit, this.multiComparator, this.random), false, true);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/OrderGlobalStep.java