val printf : attr list -> ('a, Core.Out_channel.t, unit) Core.format -> 'aval eprintf : attr list -> ('a, Core.Out_channel.t, unit) Core.format -> 'aval output_string : attr list -> Core.Out_channel.t -> string -> unitval output : attr list -> Core.Out_channel.t -> Core.Bytes.t -> int -> int -> unitval string_with_attr : attr list -> string -> string