// Add InvokerCallbackHandler first time.
TestInvokerCallbackHandler callbackHandler = new TestInvokerCallbackHandler();
client.addListener(callbackHandler, new HashMap());
assertEquals(1, callbackPollers.size());
CallbackPoller callbackPoller1 = (CallbackPoller) callbackPollers.values().iterator().next();
// Add InvokerCallbackHandler second time.
client.addListener(callbackHandler, new HashMap());
assertEquals(1, callbackPollers.size());
CallbackPoller callbackPoller2 = (CallbackPoller) callbackPollers.values().iterator().next();
assertEquals(callbackPoller2, callbackPoller1);
client.removeListener(callbackHandler);
client.disconnect();
connector.stop();