downloadFile method

Future<RxResult<String>> downloadFile({ required String savePath, ProgressCallback? onReceiveProgress, })

下载文件（Future 版本，支持 async/await）

Implementation

//    final result = await RxNet.get()
//     .setPath("https://example.com/file.zip")
//     .downloadFile(savePath: "/path/to/save/file.zip");
//       if (result.isSuccess) {
//       print("下载成功: ${result.value}");
//   }

Future<RxResult<String>> downloadFile({
  required String savePath,
  adapter.ProgressCallback? onReceiveProgress,
}) async {
  if (!(await _checkNetWork())) {
    return RxResult.error(NetworkException("Network not available"));
  }

  final url = _buildFinalUrl();
  final payload = _resolveRequestPayload();
  final file = File(savePath);

  try {
    if (!file.parent.existsSync()) {
      file.parent.createSync(recursive: true);
    }

    final adapterRequest = _buildAdapterRequest(
      url: url,
      queryParams: payload.queryParams,
      data: payload.body,
      contentType: payload.contentType,
    );

    final adapter = _requireAdapter();
    final response = await adapter.download(
      adapterRequest,
      savePath,
      onProgress: (received, total) {
        onReceiveProgress?.call(received, total > 0 ? total : received);
      },
    );

    onResponse?.call(response);
    if (response.isSuccess) {
      return RxResult(value: savePath, model: SourcesType.net);
    } else {
      throw NetworkException(
          "Download failed with status code ${response.statusCode}", null);
    }
  } on AdapterException catch (e) {
    if (e.type == AdapterExceptionType.cancel) {
      throw CancellationException("Download was cancelled", e);
    }
    throw NetworkException(e.message, e);
  } catch (e) {
    if (e is RxError) rethrow;
    throw NetworkException("Download failed: $e", e);
  }
}