code: @SuppressWarnings("unchecked")
      public void setAutoTransferringHeader(String name, String value)
      {
          Hashtable headers = getAutoTransferringHeaders();
          headers.put(name, value);
  //        setHeader(name, value);
      }
docs: Set a header that should be automatically transferred to all requests
  in a chain.  These headers will be backed up in a request attribute that
  will automatically read and transferred by all ChainedResponses.  This method
  is useful for transparently transferring the original headers sent by the client
  without forcing servlets to be specially written to transfer these headers.