       let context = UnsafePointer<T>(dispatch_get_context(ws))
       if context == nil
       { // 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
            }

      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
      }
