Freelist.Make_1
type t
= freelist
val create : min_free:int -> freelist
val alloc : freelist -> int
val free : freelist -> int -> unit
val save : t -> fn:string -> unit
val load_no_promote : fn:string -> t
val load_and_promote_reuse : fn:string -> freelist
Promote dont_reuse to do_reuse, on the basis that we are starting a new merge
val reload_and_promote_reuse : freelist -> fn:string -> unit
val debug_to_string : freelist -> string