如何在Flutter谷歌地图中显示2 LatLng作为初始位置

dependencies:
  flutter:
    sdk: flutter
  google_maps_flutter: ^1.2.0

<meta-data
    android:name="com.google.android.geo.API_KEY"
    android:value="YOUR_API_KEY"/>

GMSServices.provideAPIKey("YOUR_API_KEY")

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

class MapScreen extends StatefulWidget {
  @override
  _MapScreenState createState() => _MapScreenState();
}

class _MapScreenState extends State<MapScreen> {
  GoogleMapController mapController;

  final LatLng location1 = LatLng(37.4219999, -122.0840575);
  final LatLng location2 = LatLng(37.4279617, -122.085749);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Map'),
      ),
      body: GoogleMap(
        initialCameraPosition: CameraPosition(
          target: location1,
          zoom: 14,
        ),
        onMapCreated: (GoogleMapController controller) {
          mapController = controller;
        },
        markers: {
          Marker(
            markerId: MarkerId('location1'),
            position: location1,
            infoWindow: InfoWindow(title: 'Location 1'),
          ),
          Marker(
            markerId: MarkerId('location2'),
            position: location2,
            infoWindow: InfoWindow(title: 'Location 2'),
          ),
        },
      ),
    );
  }
}