external resize2fs : t -> string -> unit = "ocaml_guestfs_resize2fs"
external find : t -> string -> string array = "ocaml_guestfs_find"
external e2fsck_f : t -> string -> unit = "ocaml_guestfs_e2fsck_f"
+external sleep : t -> int -> unit = "ocaml_guestfs_sleep"