attachment_fu Memory Use When Uploading

Hello,

If I were to upload, say, a 250MB image using attachment_fu without any resizing or image manipulation would I need 250MB of spare RAM to handle the upload?

I ask because I'm not sure whether attachment_fu streams the data to its storage location as it arrives over HTTP or whether it builds the entire blob up in memory before writing it all in one go to the storage location.

Thanks and regards,
Andy Stewart