isFirst property
Whether this route is the bottom-most route on the navigator.
If this is true, then Navigator.canPop will return false if this route's willHandlePopInternally returns false.
If isFirst and isCurrent are both true then this is the only route on the navigator (and isActive will also be true).
Implementation
bool get isFirst {
return _navigator != null && _navigator._history.first == this;
}