@Override
    public void processAllStarts() {
        while (this.starts.hasNext()) {
            this.createProjectedTraverser(this.starts.next()).ifPresent(traverserSet::add);
        }
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/SampleGlobalStep.java