digest method
Generates the final hash digest by assembling and returning the hash state in a List<int>.
This function produces the hash digest by combining the current hash state into a single
List<int> output. It finalizes the hash if it hasn't been finished, effectively completing
the hash computation and returning the result.
Returns the List<int> containing the computed hash digest.
Implementation
List<int> digest() {
final out = List<int>.filled(digestLength, 0);
finish(out);
return out;
}