What is Data Persistor? How and when it can be used?
I can see its usage in
vendor/magento/module-cms/Controller/Adminhtml/Page/Index.php
inside execute() method
$dataPersistor = $this->_objectManager->get(\Magento\Framework\App\Request\DataPersistorInterface::class);
$dataPersistor->clear('cms_page');
Its just a class which stores data to the current user session. You can set, get and clear data from the session.
Have a look at the \Magento\Framework\App\Request\DataPersistor class SessionManagerInterface is used in every method.
You could use this to store temporary data to be used across the framework which don't need to be stored otherwise in the database.
