Because of the Google Drive StorageFile now contains yet another field,
`id`. For other storages `id` == `path`, and thus all common Requests
(such as SavesSyncRequest, DownloadFolderRequest, etc) must be using
id() instead of path(). That way these Requests won't cause id resolving
which could be quite slow (when you call it for all files in the folder,
for example).
When listing directories, you get a list of StorageFiles, which path()
is actually Google Drive id. Thus, if you list a directory recursively,
you won't be able to determine whether all files are within one
directory or have some hierarchy. I'd fix that as soon as it would be
needed.
