type 'a t
val create : cmp:('a -> 'a -> int) -> 'a t
create a min-heap on type 'a
val push : 'a t -> 'a -> unit
val pop : 'a t -> 'a Async.Deferred.t
val length : _ t -> int
val iter_and_clear : 'a t -> f:('a -> unit) -> unit
val clear : 'a t -> unit