 
   private init() {}
 
+  deinit
+  {
+    WaitQueue.dealloc(waiters)
+  }
+
   /// Initialize to an already determined state
   ///
   /// - parameter value: the value of this `Deferred`

      {
        if CAS(tail, waiter, &waiters)
        { // waiter is now enqueued
          // OSAtomicIncrement32Barrier(&waiting)
          return true
        }
      }

    }
  }

  // MARK: private methods

  /// Change the state of this `Deferred` from `.Waiting` to `.Executing`
