Optionalfilenameupload, download and delete: the stored file name.
Storage key: <projectName>/<subfolder>/<filename> (the folder itself for list).
Optionalsizeupload: the file's size in bytes.
OptionalsubfolderThe subfolder, without empty or dot-only segments.
Optionaltypeupload: the Content-Type it is stored with (from its extension).
What an upload route acts on, as passed to
authorize.