openMicrophone method

Implementation

@override
Future<Map<String, dynamic>> openMicrophone() async {
  try {
    final result = await _pluginCall.openMicrophone().toDart;
    final rawData = result.dartify() as Map?;
    return Map<String, dynamic>.from(rawData ?? {});
  } catch (e) {
    throw Exception('打开麦克风失败: $e');
  }
}