How to get folder path where user drag out?

For example i have some bytearray in memory and i want to save it on the disk. So user can drag out from app and save file to disk. But i can't find way to how to get nativePath to destination folder. (I know that i can save file in some temporary file and send command to drag out to copy this file to destination, but this is not my variant, i need to delete file after that, but i can't have any events when copying is finish...)