Swift有没有办法不仅观察对象的变化，而且观察引用的变化？

class Observable<T> {
    typealias Observer = (T) -> Void
    private var observers: [Weak<Observer>] = []
    
    func addObserver(_ observer: @escaping Observer) {
        observers.append(Weak(observer))
    }
    
    func removeObserver(_ observer: @escaping Observer) {
        observers.removeAll { $0.value === observer }
    }
    
    func notifyObservers(_ value: T) {
        observers.compactMap { $0.value }.forEach { $0(value) }
    }
}

class Weak<T: AnyObject> {
    weak var value: T?
    
    init(_ value: T) {
        self.value = value
    }
}

// 使用示例
class MyClass {
    let observable = Observable<Int>()
    
    func doSomething() {
        // 模拟变化
        observable.notifyObservers(42)
    }
}

let myClass = MyClass()
myClass.observable.addObserver { newValue in
    print("New value: \(newValue)")
}

myClass.doSomething() // 输出: New value: 42

import Combine

class MyClass {
    @Published var value: Int = 0
    
    func doSomething() {
        value = 42
    }
}

let myClass = MyClass()
let cancellable = myClass.$value.sink { newValue in
    print("New value: \(newValue)")
}

myClass.doSomething() // 输出: New value: 42

class Weak<T: AnyObject> {
    weak var value: T?
    
    init(_ value: T) {
        self.value = value
    }
}

private var observers: Set<Weak<Observer>> = []