If you're using Symfony's UploadedFile,
please be aware that if you call this method
_after_ you call @move, you will most likely get
some obscenely untraceable error, that says:
`stat failed`
Which if you really think about it, it does makes sense,
the file has been moved by Symfony, but getSize is in SplFileInfo,
and SplFileInfo doesn't know that the file has been moved.
Weirdly enough, that error doesn't come on my work mac :|