file method
Implementation
@override
Future<MultipartUpload> file(String name, {Encoding encoder = utf8}) async {
final payload = await (request.payload(encoder: encoder)
as FutureOr<Map<dynamic, dynamic>>);
final multiPart = await payload[name];
if (multiPart is MultipartUpload) {
return multiPart;
} else {
Get.log('Incorrect format, upload the file as Multipart/formdata',
isError: true);
return MultipartUpload(null, null, null, null);
}
}