try {
Constructor<IOHandler> ioHandlerCtr = IOHandler.class.getDeclaredConstructor(SIPTransactionStack.class);
ioHandlerCtr.setAccessible(true);
Class[] ctrArgs = new Class[] {SIPTransactionStack.class};
Object[] ctrValues = new Object[] {Shootme.this.protocolObjects.sipStack};
IOHandler ioHandler = (IOHandler) ioHandlerCtr.newInstance(ctrValues);
Field ioHandlerField = SIPTransactionStack.class.getDeclaredField("ioHandler");
ioHandlerField.setAccessible(true);
ioHandler = (IOHandler) ioHandlerField.get(Shootme.this.protocolObjects.sipStack);
ioHandler.closeAll();
Request request = requestEvent.getRequest();
Response response = protocolObjects.messageFactory.createResponse(180, request);
ToHeader toHeader = (ToHeader) response.getHeader(ToHeader.NAME);
toHeader.setTag("4321");