userGestureEnabled property
Whether a gesture can be started by the user.
Returns true if the user can swipe to a previous route.
Returns false once isUserGestureInProgress is true, but isUserGestureInProgress can only become true if userGestureEnabled was true first.
This should only be used between frames, not during build.
Implementation
@override
bool get userGestureEnabled => !isDeactivated && (!hasRoute || (route!.isActive && super.userGestureEnabled));