merkle function
Get Merkle Tree
Implementation
List<Uint8List> merkle(List<Uint8List> values, DigestFn digestFn) {
if (values.length == 1) return List.from(values);
List<List<Uint8List>> levels = [values];
var level = values;
do {
level = _derive(level, digestFn);
levels.add(level);
} while (level.length > 1);
return levels.expand((i) => i).toList();
}