String contentKey = NetworkTestUtil.randomString();
// create a message with target node B
TestMessageWithReplyMaxSending message = new TestMessageWithReplyMaxSending(nodeB.getNodeId(),
contentKey);
// create and add a callback handler
TestCallBackHandlerMaxSendig callBackHandler = message.new TestCallBackHandlerMaxSendig(nodeA);
message.setCallBackHandler(callBackHandler);
// send message
assertTrue(nodeA.getMessageManager().send(message, getPublicKey(nodeB)));