当在Flutter的SearchAnchor/SearchBar小部件中输入搜索词时，按回车键提交搜索是很自然的。不过，对于SearchAnchor/SearchBar，似乎没有与TextField的onSubmitted回调等效的回调。我如何检测到输入键被按下，以便我可以关闭搜索锚点/搜索栏并显示搜索结果？
注意：这个问题是指Flutter 3.10.0中首次发布的SearchBar / SearchAnchor小部件
我已经研究了SearchAnchor/SearchBar API，并尝试了各种方法来发现用户何时点击回车键，如以下代码片段所示：

import 'package:flutter/material.dart';

class SearchView extends StatefulWidget {
  const SearchView({super.key});

  @override
  State<SearchView> createState() => _SearchViewState();
}

class _SearchViewState extends State<SearchView> {
  final searchController = SearchController();

  @override
  void initState() {
    searchController.addListener(() {
      // Not called when enter key pressed.
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return SearchAnchor(
      // No onSubmitted callback parameter.
      searchController: searchController,
      builder: (context, controller) {
        return SearchBar(
          // No onSubmitted callback parameter
          onTap: () => controller.openView(),
          controller: controller,
          onChanged: (text) {
            // Not called when enter key pressed.
          },
        );
      },
      suggestionsBuilder: (context, controller) {
        // Enter character not found in controller.text
        return [];
      },
      // No onSubmitted callback.
    );
  }
}