var tree = new KdTree<float, int>(2, new FloatMath());
tree.Add(new[] { 50.0f, 80.0f }, 100);
tree.Add(new[] { 20.0f, 10.0f }, 200);
var nodes = tree.GetNearestNeighbours(new[] { 30.0f, 20.0f }, 1);