type error = errortype t = tval length : fd -> (int64, error) Stdlib.result Lwt.tval map : fd -> ?pos:int64 -> int -> (Cstruct.t, error) Stdlib.result Lwt.tval close : fd -> (unit, error) Stdlib.result Lwt.t2-FS.Mappertype error = errortype t = tval length : fd -> (int64, error) Stdlib.result Lwt.tval map : fd -> ?pos:int64 -> int -> (Cstruct.t, error) Stdlib.result Lwt.tval close : fd -> (unit, error) Stdlib.result Lwt.t