`?event_system:Unixqueue.event_system ->
?onempty:(Ftp_client.ftp_state -> unit) ->
?onclose:(unit -> unit) ->
?onerrorstate:(exn -> unit) ->
?onusererror:(exn -> unit) ->
Unix.file_descr ->
object
method abort : unit -> unit
method add_cmd :
?onreply:(Ftp_client.ftp_state -> Ftp_client.reply -> unit) ->
Ftp_client.cmd -> unit
method event_system : Unixqueue.event_system
method ftp_state : Ftp_client.ftp_state
method is_empty : bool
method run : unit -> unit
method send_abort : unit -> unit
method state : unit Uq_engines.engine_state
end`