Obtaining the user's iCloud account status using CloudKit

AccountStatus.swift

CKContainer.default().accountStatus { status, error in
    if let error = error {
      // some error occurred (probably a failed connection, try again)
    } else {
        switch status {
        case .available:
          // the user is logged in
        case .noAccount:
          // the user is NOT logged in
        case .couldNotDetermine:
          // for some reason, the status could not be determined (try again)
        case .restricted:
          // iCloud settings are restricted by parental controls or a configuration profile
        }
    }
}