code: private Jingle receiveResult(IQ iq) throws XMPPException, SmackException, InterruptedException {
          Jingle response = null;
  
          sendTransportCandidatesOffer();
          setNegotiatorState(JingleNegotiatorState.PENDING);
  
          return response;
      }
docs: The other endpoint has partially accepted our invitation: start
  offering a list of candidates.
  
  @return an IQ packet
  @throws XMPPException
  @throws SmackException
  @throws InterruptedException