IsAttrUnset checks the xattr.ENOATTR from the xattr package which redifines it as ENODATA on platforms that do not natively support it (eg.

The os error is buried inside the fs.PathError error.

IsNotExist checks if there is a os not exists error buried inside the xattr error, as we cannot just use os.IsNotExist().

NewMessagePackBackend returns a new MessagePackBackend instance.

NewMessageBackend returns a new XattrsBackend instance.

MessagePackBackend persists the attributes in messagepack format inside the file.

NullBackend is the default stub backend, used to enforce the configuration of a proper backend.

XattrsBackend stores the file attributes in extended attributes.

Backend defines the interface for file attribute backends.