public static String[] vertexComputeKeysAsArray(final Set<VertexComputeKey> vertexComputeKeySet) {
        return VertexProgramHelper.vertexComputeKeysAsSet(vertexComputeKeySet).toArray(new String[vertexComputeKeySet.size()]);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/util/VertexProgramHelper.java