final SimpleCallbackHandler callbackHandler = new SimpleCallbackHandler();
metadata.put(ServerInvoker.BLOCKING_MODE, ServerInvoker.BLOCKING);
metadata.put(ServerInvoker.BLOCKING_TIMEOUT, "10000");
client.addListener(callbackHandler, metadata);
assertEquals(1, callbackPollers.size());
CallbackPoller callbackPoller = (CallbackPoller) callbackPollers.values().iterator().next();
field = CallbackPoller.class.getDeclaredField("blockingPollerThread");
field.setAccessible(true);
Thread blockingPollerThread = (Thread) field.get(callbackPoller);
assertNotNull(blockingPollerThread);
log.info("client added callback handler for pull callbacks");