type 'a t
val create : unit -> 'a t
val pop : ?picky:('a -> bool) -> ?destroy:bool Stdlib.ref -> 'a t -> 'a
val push : 'a t -> 'a -> unit
val set_order : 'a t -> ('a -> 'a -> int) -> unit
val wait_until_n_are_waiting_and_queue_empty : int -> 'a t -> unit
val broadcast : 'a t -> unit
val wait_until_n_are_waiting_then_snapshot : int -> 'a t -> 'a list
val clear : 'a t -> unit
val clear_saving : 'a t -> ('a -> 'b option) -> 'b list
val is_empty : 'a t -> bool
exception
BeingDestroyed
val destroy : 'a t -> unit
val length : 'a t -> int