code: void copyTransients(JsHdrsImpl copy) {
          copy.cachedMessageWaitTime = cachedMessageWaitTime;
          copy.cachedReliability = cachedReliability;
          copy.cachedPriority = cachedPriority;
          copy.cachedMessageHandle = cachedMessageHandle;
          copy.flags = flags;
          copy.gotFlags = gotFlags;
      }
docs: Copies any 'interesting' transient data into the given message copy.
  
  Sub-classes should override this (calling super.copyTransients()) to copy
  any transient cached data into new copies of messages.
  
  Note that:
  The part caches must NOT be copied.
  wasTimeToLiveChanged need not be copied as it is only used during a Mediation
  deliveryCount should not be copied as it is only a temporary value
  
  @param copy The message copy whose transients should be set to the same as this one.