Concurrent (infer.IBase.Concurrent)

module Queue : sig ... end

A thread-safe queue.

module type Hashtbl = sig ... end

module MakeHashtbl
  (H : Stdlib.Hashtbl.S) : 
  Hashtbl with type key = H.key with module Hash = H

a thread safe hashtable

module type CacheS = sig ... end

module MakeCache (Key : sig ... end) : CacheS with type HQ.key = Key.t