toJson method
Returns a JSON object representation of this instance.
Implementation
Map<String,dynamic> toJson() {
  Map<String, dynamic> data = {
    "metadata": {"version": 4.5, "type": 'Curve', "generator": 'Curve.toJson'}
  };
  data["arcLengthDivisions"] = arcLengthDivisions;
  data["type"] = runtimeType.toString();
  return data;
}