       let context = UnsafePointer<T>(dispatch_get_context(ws))
       if context == UnsafePointer.null()
       { // not a normal code path.
+        assertionFailure(__FUNCTION__)
         dispatch_semaphore_signal(nil)
         return nil
       }

      let context = UnsafePointer<T>(dispatch_get_context(ws))
      if context == nil
      { // not a normal code path.
        dispatch_semaphore_signal(nil)
        return nil
      }

      let pointer = UnsafeMutablePointer<T>(dispatch_get_context(rs))
      if pointer == UnsafeMutablePointer.null()
      { // not a normal code path.
        assertionFailure(__FUNCTION__)
        dispatch_semaphore_signal(nil)
        return false
      }
