An observable property wrapper for UserDefaults

UserDefault.swift

import Foundation
import Combine

@propertyWrapper
final class UserDefault<Wrapped>: NSObject, ObservableObject {
    
    typealias Validator = (Wrapped) -> (Wrapped)
    
    private let suite: UserDefaults
    private let key: String
    private let defaultValue: Wrapped
    private let validator: Validator
    
    init(suite: UserDefaults = .standard, key: String, defaultValue: Wrapped, validator: @escaping Validator = ({ $0 })) {
        self.suite = suite
        self.key = key
        self.defaultValue = defaultValue
        self.validator = validator
        
        super.init()
        
        suite.register(defaults: [key: defaultValue])
        suite.addObserver(self, forKeyPath: key, options: .prior, context: nil)
    }
    
    var wrappedValue: Wrapped {
        get { validator(suite.object(forKey: key) as? Wrapped ?? defaultValue) }
        set { suite.set(validator(newValue), forKey: key) }
    }
    
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        objectWillChange.send()
    }
    
}

Could you please explain how to use this? How does one get a Publisher for the defaults-backed value? Thank you.