`object
method virtual close_out : unit -> unit
method virtual flush : unit -> unit
method virtual output : string -> int -> int -> int
method output_buffer : Buffer.t -> unit
method output_byte : int -> unit
method output_channel : ?len:int -> in_obj_channel -> unit
method output_char : char -> unit
method output_string : string -> unit
method virtual pos_out : int
method really_output : string -> int -> int -> unit
end`