(A.key -> A.value Lwt.t) ->
?timer:float ->
int ->
object
  method add : A.key -> A.value -> unit
  method clear : unit -> unit
  method find : A.key -> A.value Lwt.t
  method find_in_cache : A.key -> A.value
  method remove : A.key -> unit
  method size : int
end