This event is fired before the contents of a file gets set / replaced. This allows to further analyze or modify the content of a file before it is written by the driver.
Method: getFile() Description: Returns the file object. ReturnType: TYPO3CMSCoreResourceFileInterface
Method: getContent() Description: Returns the current file content. ReturnType: string
Method: setContent(string $content) Description: Set / Overwrite the current file content. ReturnType: void