private void copyHaltedTraversersFromMemory(final Vertex vertex) {
        final Collection<Traverser.Admin<Vertex>> traversers = this.haltedTraversersIndex.get(vertex);
        if (traversers != null) {
            final TraverserSet<Vertex> newHaltedTraversers = new TraverserSet<>();
            newHaltedTraversers.addAll(traversers);
            vertex.property(VertexProperty.Cardinality.single, TraversalVertexProgram.HALTED_TRAVERSERS, newHaltedTraversers);
        }
    }
Identifies "Connected Component" instances in a graph by assigning a component identifier (the lexicographically
least string value of the vertex in the component) to each vertex.

@author Stephen Mallette (http://stephen.genoprime.com)
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/clustering/connected/ConnectedComponentVertexProgram.java