val print_s : ?mach:unit -> Sexplib.Sexp.t -> unit
val printf : ('a, unit, string, unit) Stdlib.format4 -> 'a
val fprintf : Async_unix.Writer.t -> ('a, unit, string, unit) Stdlib.format4 -> 'a
val eprintf : ('a, unit, string, unit) Stdlib.format4 -> 'a