/**
* Initializes the message bus by setting up the <tt>recvBuilder</tt> to accept responses. Also, initializes the
* incoming timer to ensure the client's polling with the server is active.
*/
private void initializeMessagingBus() {
GWT.runAsync(new RunAsyncCallback() {
@Override
public void onFailure(Throwable reason) {
showError("failed to load RPC script from server", reason);
}