codeUnits gets you a List<int>
Uint8List.fromList(...) converts List<int> to Uint8List
String.fromCharCodes(...) converts List<int> or Uint8List to String
List<int> list = 'xxx'.codeUnits; Uint8List bytes = Uint8List.fromList(list); String string = String.fromCharCodes(bytes);

`codeUnits` gets you a `List<int>` `Uint8List.fromList(...)` converts `List<int>` to `Uint8List` `String.fromCharCodes(...)` converts `List<int>` or `Uint8List` to `String`
List<int> list = 'xxx'.codeUnits; Uint8List bytes = Uint8List.fromList(list); String string = String.fromCharCodes(bytes);