code: public void onCandidate(long sessionId, int index, String id, String sdp) {
          send(new PeerConnectionActor.OnCandidate(sessionId, index, id, sdp));
      }
docs: Call this method when new candidate arrived from other peer
  
  @param index index of media in sdp
  @param id    id of candidate
  @param sdp   sdp of candidate