code: public static void assertRequestNotReceived(String method, long sequenceNumber,
        MessageListener obj) {
      assertRequestNotReceived(null, method, sequenceNumber, obj);
    }
docs: Asserts that the given message listener object has not received a request with the indicated
  CSeq method and sequence number.
  
  @param method The CSeq method to verify absent (SipRequest.INVITE, etc.)
  @param sequenceNumber The CSeq sequence number to verify absent
  @param obj The MessageListener object (ie, SipCall, Subscription, etc.).