val is_accessible_directory : ?create_if_missing:unit ‑> string ‑> unit Async.Deferred.Or_error.tval safely_ls_dir : string ‑> string list Async.Deferred.Or_error.tval unlink : string ‑> unit Async.Deferred.Or_error.tval rename : src:string ‑> dst:string ‑> unit Async.Deferred.Or_error.t