correct method

void correct(
  1. Duration duration
)

If you need override current duration add or subtract _durationLeft with other duration & countUp is true will automate add _durationLeft & countUp is fale will automate subtract _durationLeft

Implementation

void correct(Duration duration) {
  if (_isCountUp) {
    add(duration);
  } else {
    subtract(duration);
  }
}