@Override
        public boolean waitUntilDone(long timeoutMs) throws InterruptedException {
            builder.append("waitUntilDone : " + timeoutMs + "\n");
            if (synchronousWaitUntilDone) {
                synchronized (this) {
                    waiting = true;
                }
                return super.waitUntilDone(timeoutMs);
            }
            return isDone();
        }
Test that using an id.user=foo selection only tries to visit a single
superbucket for that user.
documentapi/src/test/java/com/yahoo/documentapi/messagebus/MessageBusVisitorSessionTestCase.java