This event is fired before a file is about to be copied within a Resource Storage / Driver. The folder represents the "target folder".
This allows to further analyze or modify the file or metadata before it is written by the driver.
Method: getFile() Description: Returns the file object. ReturnType: TYPO3CMSCoreResourceFileInterface
Method: getFolder() Description: Returns the folder where the file is stored. ReturnType: TYPO3CMSCoreResourceFolder