uploadFile method
Start a background upload task.
Returns the upload ID if successful, null otherwise.
Implementation
@override
Future<String?> uploadFile(UploadTask task) async {
try {
final result = await methodChannel.invokeMethod<String>(
'uploadFile',
task.toMap(),
);
return result;
} on PlatformException catch (e) {
debugPrint('Failed to start upload: ${e.message}');
return null;
}
}