@Override
    public <A> SparqlTraversalSource withSack(final Supplier<A> initialValue, final UnaryOperator<A> splitOperator, final BinaryOperator<A> mergeOperator) {
        return (SparqlTraversalSource) super.withSack(initialValue, splitOperator, mergeOperator);
    }
A {@link TraversalSource} implementation that spawns {@link SparqlTraversal} instances.

@author Stephen Mallette (http://stephen.genoprime.com)
sparql-gremlin/src/main/java/org/apache/tinkerpop/gremlin/sparql/process/traversal/dsl/sparql/SparqlTraversalSource.java