如何处理swift model类上的额外参数

struct MyModel: Codable {
    let property1: String
    let property2: Int

    enum CodingKeys: String, CodingKey {
        case property1
        case property2
        case unknown
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        property1 = try container.decode(String.self, forKey: .property1)
        property2 = try container.decode(Int.self, forKey: .property2)

        // 处理额外参数
        let additionalValues = try container.decode([String: String].self, forKey: .unknown)
        // 进行额外参数的处理逻辑
    }
}

struct MyModel {
    let property1: String
    let property2: Int
}

extension MyModel {
    var additionalParameter: String {
        // 处理额外参数的逻辑
        return "additional parameter value"
    }

    func processAdditionalParameter() {
        // 处理额外参数的方法逻辑
    }
}