Retrieve persisted long-lived operations, reassign their completion blocks and add them back to a CKDatabase

RetrieveLongLivedOperations.swift

CKContainer.defaultContainer().fetchAllLongLivedOperationIDsWithCompletionHandler { (operationIDs, error) in
    guard let operationIDs = operationIDs else {
        print("error:", error)
        return
    }
    operationIDs.forEach { (operationID) in
        CKContainer.defaultContainer().fetchLongLivedOperationWithID(operationID) { (operation, error) in
            guard let operation = operation else {
                print("Unable to fetch operation with ID", operationID, "error:", error)
                return
            }
            if let modifyOperation = operation as? CKModifyRecordsOperation {
                modifyOperation.modifyRecordsCompletionBlock = { (savedRecords, _, error) in
                    print("Operation with ID", operation.operationID, "saved records", savedRecords, "error", error)
                }
                CKContainer.defaultContainer().publicCloudDatabase.addOperation(modifyOperation)
            }
        }
    }
}