public MultipointBuilderEx( 
   IEnumerable<Coordinate2D> coordinate2Ds,
   SpatialReference spatialReference
)

{
  Coordinate2D[] coordinate2Ds = new Coordinate2D[] { new Coordinate2D(1, 2), new Coordinate2D(-1, -2) };
  SpatialReference sr = SpatialReferences.WGS84;

  MultipointBuilderEx builder = new MultipointBuilderEx(coordinate2Ds, sr);

  // builder.PointCount = 2

  builder.HasZ = true;
  // builder.Zs.Count = 2
  // builder.Zs[0] = 0
  // builder.Zs[1] = 0

  builder.HasM = true;
  // builder.Ms.Count = 2
  // builder.Ms[0] = NaN
  // builder.Ms[1] = NaN

  builder.HasID = true;
  // builder.IDs.Count = 2
  // builder.IDs[0] = 0
  // builder.IDs[1] = 0

  // set it empty
  builder.SetEmpty();
  // builder.Coords.Count = 0
  // builder.Zs.Count = 0
  // builder.Ms.Count = 0
  // builder.IDs.Count = 0


  // reset coordinates
  List<Coordinate2D> inCoords = new List<Coordinate2D>() { new Coordinate2D(1, 2), new Coordinate2D(3, 4), new Coordinate2D(5, 6) };
  builder.Coordinate2Ds = inCoords;
  // builder.Coords.Count = 3
  // builder.HasZ = true
  // builder.HasM = true
  // builder.HasID = true

  double[] zs = new double[] { 1, 2, 1, 2, 1, 2 };
  builder.Zs = zs;
  // builder.Zs.Count = 6

  double[] ms = new double[] { 0, 1 };
  builder.Ms = ms;
  // builder.Ms.Count = 2

  // coordinates are now   (x, y, z, m, id)
  //  (1, 2, 1, 0, 0), (3, 4, 2, 1, 0) (5, 6, 1, NaN, 0)

  MapPoint mapPointFromBuilder = builder.GetPoint(2);
  // mapPoint.HasZ = true
  // mapPoint.HasM = true
  // mapPoint.HasID = true
  // mapPoint.Z  = 1
  // mapPoint.M = NaN
  // mapPoint.ID = 0

  // add an M to the list
  builder.Ms.Add(2);
  // builder.Ms.count = 3

  // coordinates are now   (x, y, z, m, id)
  //  (1, 2, 1, 0, 0), (3, 4, 2, 1, 0) (5, 6, 1, 2, 0)

  // now get the 2nd point again; it will now have an M value
  mapPointFromBuilder = builder.GetPoint(2);
  // mapPoint.M = 2


  int[] ids = new int[] { -1, -2, -3 };
  // assign ID values
  builder.IDs = ids;

  // coordinates are now   (x, y, z, m, id)
  //  (1, 2, 1, 0, -1), (3, 4, 2, 1, -2) (5, 6, 1, 2, -3)


  // create a new point
  MapPoint pointFromBuilder = MapPointBuilderEx.CreateMapPoint(-300, 400, 4);
  builder.SetPoint(2, pointFromBuilder);

  // coordinates are now   (x, y, z, m, id)
  //  (1, 2, 1, 0, -1), (3, 4, 2, 1, -2) (-300, 400, 4, NaN, 0)


  builder.RemovePoints(1, 3);
  // builder.PointCount = 1
}