Flutter package Chewie:如何知道视频控制器在不播放视频的情况下将第一帧放到屏幕上？

import 'package:flutter/material.dart';
import 'package:chewie/chewie.dart';
import 'package:video_player/video_player.dart';

class VideoPlayerScreen extends StatefulWidget {
  @override
  _VideoPlayerScreenState createState() => _VideoPlayerScreenState();
}

class _VideoPlayerScreenState extends State<VideoPlayerScreen> {
  ChewieController _chewieController;
  VideoPlayerController _videoPlayerController;

  @override
  void initState() {
    super.initState();
    _videoPlayerController = VideoPlayerController.network('https://example.com/video.mp4');
    _chewieController = ChewieController(
      videoPlayerController: _videoPlayerController,
      autoInitialize: true,
      looping: true,
      // 其他配置项...
    );

    _videoPlayerController.initialize().then((_) {
      setState(() {
        // 视频加载完成后，获取第一帧的图像
        final image = _videoPlayerController.value.image;
        // 在这里可以将第一帧的图像显示在屏幕上
      });
    });
  }

  @override
  void dispose() {
    _chewieController.dispose();
    _videoPlayerController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Video Player'),
      ),
      body: Center(
        child: Chewie(
          controller: _chewieController,
        ),
      ),
    );
  }
}