notifiedByParent method Null safety
protected">@protected
The parent of this child back button dispatcher decide to let this child to handle the invoke the callback request in BackButtonDispatcher.invokeCallback.
Return a boolean future with true if this child will handle the request; otherwise, return a boolean future with false.
Implementation
@protected
Future<bool> notifiedByParent(Future<bool> defaultValue) {
return invokeCallback(defaultValue);
}