Swim.Pending_acks

type waiter = {
  promise : string option Eio.Promise.t;
  resolver : string option Eio.Promise.u;
}

type t

val create : unit -> t

val register : t -> seq:int -> waiter

val complete : t -> seq:int -> payload:string option -> bool

val wait : 
  waiter ->
  timeout:float ->
  clock:_ Eio.Time.clock ->
  string option option

val cancel : t -> seq:int -> unit

val pending_count : t -> int