FLUTTER，DART:如何将list<Model>转换为地图

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

class Model {
  double latitude;
  double longitude;

  Model({this.latitude, this.longitude});
}

class MapScreen extends StatelessWidget {
  List<Model> modelList = [
    Model(latitude: 37.421998, longitude: -122.084),
    Model(latitude: 37.7749, longitude: -122.4194),
    Model(latitude: 34.0522, longitude: -118.2437),
  ];

  @override
  Widget build(BuildContext context) {
    List<Marker> markers = modelList.map((model) {
      return Marker(
        markerId: MarkerId('${model.latitude}-${model.longitude}'),
        position: LatLng(model.latitude, model.longitude),
      );
    }).toList();

    return Scaffold(
      appBar: AppBar(
        title: Text('Map'),
      ),
      body: GoogleMap(
        initialCameraPosition: CameraPosition(
          target: LatLng(37.421998, -122.084),
          zoom: 10,
        ),
        markers: Set<Marker>.from(markers),
      ),
    );
  }
}