decodeHexString function
Implementation
Uint8List decodeHexString(String input) {
assert(input.length % 2 == 0, 'Input needs to be an even length.');
return Uint8List.fromList(
List.generate(
input.length ~/ 2,
(i) => int.parse(input.substring(i * 2, (i * 2) + 2), radix: 16),
).toList(),
);
}