docs: void copyTransients(JsHdrsImpl copy) {
          copy.cachedMessageWaitTime = cachedMessageWaitTime;
          copy.cachedReliability = cachedReliability;
          copy.cachedPriority = cachedPriority;
          copy.cachedMessageHandle = cachedMessageHandle;
          copy.flags = flags;
          copy.gotFlags = gotFlags;
      }