unsafe-unretained

Is there any way to check an unowned(safe) Swift reference for "availability"? So, I am looking for a hypothetical function like isReferenceAccessible in this example: func someMethod() { someAsyncOperation(parameters) { [unowned(safe) self] in guard isReferenceAccessible(self) else { return } self.someAnotherMethod() } } Disclaimer: This question not about weak references! I am aware of how strong , unowned and weak references work. And I don't want to use weak references (because it can be slow, and mutable). I know that unowned(safe) references still be allocated even if it is already