reset method
Resets the hash computation to its initial state.
Implementation
@override
HMAC reset() {
final innerState = _innerKeyedState;
if (innerState != null) {
_inner.restoreState(innerState);
}
final outState = _outerKeyedState;
if (outState != null) {
_outer.restoreState(outState);
}
_finished = false;
return this;
}