type error = errortype t = tval exists : t -> Fpath.t -> (bool, error) Stdlib.result Lwt.tval create : t -> Fpath.t -> (bool, error) Stdlib.result Lwt.tval delete : t -> Fpath.t -> (unit, error) Stdlib.result Lwt.tval current : t -> (Fpath.t, error) Stdlib.result Lwt.t