Best way to construct connected clipped Voronoi graph? - voronoiDiagram LineSegments don't line up

[jceipek]

I just finished porting as3delaunay to C# (https://github.com/jceipek/Unity-delaunay) and I'm trying to figure out how to best expose a graph of connected nodes for the Voronoi results. It seems that adjacent LineSegments produced by Voronoi.voronoiDiagram do not have perfectly overlapping vertices; even the individual coordinates of the vertices of the LineSegments are sometimes off by a small margin.

Could you perhaps offer some suggestions as to how to create such a graph?
At the moment, I'm using a dictionary in a manner similar to the way the kruskal function works but indexing on a 2-Tuple with custom hash and equality functions to make nearby vertices hash the same way, but that seems quite kludgy and doesn't always work perfectly:

public struct Tuple : System.IEquatable<Tuple>
{
    readonly float x;
    readonly float y;

    public Tuple (float first, float second)
    {
        this.x = first;
        this.y = second;
    }

    public float X { get { return x; } }
    public float Y { get { return y; } }

    public override int GetHashCode ()
    {
        return (Mathf.RoundToInt (x)).GetHashCode () ^ (Mathf.RoundToInt (y)).GetHashCode ();
    }

    public override bool Equals (object obj)
    {
        if (obj == null || GetType () != obj.GetType ()) {
            return false;
        }
        return Equals ((Tuple)obj);
    }

    public bool Equals (Tuple other)
    {
        return Mathf.Approximately (other.x, x) && Mathf.Approximately (other.y, y);
    }
}

// After setting up lineSegments = voronoiInstance.voronoiDiagram(points,colors,rect)
Dictionary<Tuple,Node> network = new Dictionary<Tuple,Node> ();
        for (int i = 0; i< lineSegments.Count; i++) {
            Tuple p0 = new Tuple (((Vector2)lineSegments [i].p0).x, ((Vector2)lineSegments [i].p0).y);
            if (!network.ContainsKey (p0)) {
                network [p0] = new Node ();
            }

            Tuple p1 = new Tuple (((Vector2)lineSegments [i].p1).x, ((Vector2)lineSegments [i].p1).y);
            if (!network.ContainsKey (p1)) {
                network [p1] = new Node ();
            }

            if (i == r0) {
                t_a = network [p0];
            } else if (i == r1) {
                t_b = network [p1];
            }

            ConnectNodes (network [p0], network [p1]);
        }