Simple future publishers for SKCloudServiceController

SKCloudServiceController+Combine.swift

//
//  StoreKit+Combine.swift
//
//  Created by Eric Lewis on 12/11/20.
//

import StoreKit
import Combine

extension SKCloudServiceController {
    func requestUserTokenPublisher(for developerToken: String) -> Future<String, Error> {
        Future { finished in
            self.requestUserToken(forDeveloperToken: developerToken) {
                if let token = $0 {
                    finished(.success(token))
                } else if let error = $1 {
                    finished(.failure(error))
                }
            }
        }
    }
    
    func requestCapabilitiesPublisher() -> Future<SKCloudServiceCapability, Error> {
        Future { finished in
            self.requestCapabilities {
                guard let error = $1 else {
                    finished(.success($0))
                    return
                }
                
                finished(.failure(error))
            }
        }
    }
    
    func requestStorefrontIdentifierPublisher() -> Future<String, Error> {
        Future { finished in
            self.requestStorefrontIdentifier {
                if let storefrontIdentifier = $0 {
                    finished(.success(storefrontIdentifier))
                } else if let error = $1 {
                    finished(.failure(error))
                }
            }
        }
    }
    
    func requestStorefrontCountryCodePublisher() -> Future<String, Error> {
        Future { finished in
            self.requestStorefrontCountryCode {
                if let storefrontCountryCode = $0 {
                    finished(.success(storefrontCountryCode))
                } else if let error = $1 {
                    finished(.failure(error))
                }
            }
        }
    }
}

probably not great but do let me know what to change / add. lazy!