cancelAfter method
Schedules a Cancel operation on this CancellationTokenSource.
Implementation
void cancelAfter(Duration delay) {
_throwIfDisposed();
if (isCancellationRequested) {
return;
}
if (delay == Duration.zero) {
_state = _notifyingCompleteState;
}
_timer ??= Timer(delay, () => onTimer(this));
}