roimulia

    func findContactsOnBackgroundThread ( completionHandler:@escaping (_ contacts:[CNContact]?)->()) {
        
        DispatchQueue.global(qos: .userInitiated).async(execute: { () -> Void in
            
            let keysToFetch = [CNContactFormatter.descriptorForRequiredKeys(for: .fullName),CNContactPhoneNumbersKey,CNContactViewController.descriptorForRequiredKeys()] as! [CNKeyDescriptor] //CNContactIdentifierKey
            let fetchRequest = CNContactFetchRequest( keysToFetch: keysToFetch)
            var contacts = [CNContact]()

            fetchRequest.unifyResults = true
            fetchRequest.sortOrder = .none