@Override
    public TraversalSideEffects clone() {
        try {
            final MemoryTraversalSideEffects clone = (MemoryTraversalSideEffects) super.clone();
            clone.sideEffects = this.sideEffects.clone();
            return clone;
        } catch (final CloneNotSupportedException e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/traversal/MemoryTraversalSideEffects.java