public void processResponse(ResponseEvent responseReceivedEvent) {
if ( responseReceivedEvent.getResponse().getStatusCode() == Response.OK) {
Dialog d = responseReceivedEvent.getDialog();
try {
Request ack = d.createAck(1);
// Added Thread.sleep to avoid regression on the test
// as ACKs arriving at the same time may create race condition
// where the ACK is removing from pending transactions by loose dialog validation
// but re created by the next ACK coming in line and thus the EventScanner
// sipStack.findPendingTransaction(sipRequest.getTransactionId()) gives transaction already exists