/// AI回复服务接口
abstract class AiService {
  /// 非流式输出方法
  Future<String> sendMessage({
    required List<Map<String, String>> messages,
    String? systemPrompt,
    String? userProperties,
  });

  /// 流式输出方法
  Stream sendMessageStream({
    required List<Map<String, String>> messages,
    String? systemPrompt,
    String? userProperties,
  });
}