pushOverlay method
Puts the overlay route name
on top of the navigation stack.
If name
was already registered as a name of an overlay route, then this
method is equivalent to pushNamed. If not, then a new OverlayRoute
will be created based on the overlay with the same name within the root
game.
Implementation
void pushOverlay(String name) {
if (_routes.containsKey(name)) {
assert(_routes[name] is OverlayRoute, '"$name" is not an overlay route');
pushNamed(name);
} else {
pushRoute(OverlayRoute.existing(), name: name);
}
}