setStep method
Implementation
void setStep(int stepIndex, {String? label}) {
final next = stepIndex.clamp(0, _stepCount);
if (next < _currentStep) return;
if (next > _currentStep) {
for (int s = _currentStep; s < next; s++) {
_finishedSteps.add(s);
}
}
_currentStep = next;
_emit(currentLabel: label);
}