toMap method Null safety

Implementation

@override
Map<String, Object?> toMap() {
  return {
    'from': this.from?.toMap(),
    'to': this.to?.toMap(),
    'wayPointsArray': this.wayPointsArray?.map((e) => e.toMap()).toList(),
    'drivingPolicy': this.drivingPolicy?.index,
    'drivingRequestTrafficType': this.drivingRequestTrafficType?.index
  };
}