object
  method private virtual cleanup : unit
  method destroy : unit
  method fake_io : Unix.file_descr -> unit
  method fork : unit
  method virtual iter : bool -> unit
  method on_readable :
    Unix.file_descr -> (Lwt_engine.event -> unit) -> Lwt_engine.event
  method on_timer :
    float -> bool -> (Lwt_engine.event -> unit) -> Lwt_engine.event
  method on_writable :
    Unix.file_descr -> (Lwt_engine.event -> unit) -> Lwt_engine.event
  method readable_count : int
  method private virtual register_readable :
    Unix.file_descr -> (unit -> unit) -> unit Stdlib.Lazy.t
  method private virtual register_timer :
    float -> bool -> (unit -> unit) -> unit Stdlib.Lazy.t
  method private virtual register_writable :
    Unix.file_descr -> (unit -> unit) -> unit Stdlib.Lazy.t
  method timer_count : int
  method transfer : Lwt_engine.abstract -> unit
  method writable_count : int
end