/// <summary>
 /// Returns true if the given vertex has neighbour as a neighbour.
 /// </summary>
 /// <param name="vertexId"></param>
 /// <param name="neighbour"></param>
 /// <returns></returns>
 public bool HasArc(uint vertexId, uint neighbour)
 {
     return(_graph.HasArc(vertexId, neighbour));
 }