void waitUntilSet(Duration timeout) {
        Instant end = Instant.now().plus(timeout);
        while (Instant.now().isBefore(end)) {
            if (latestRequest != null)
                return;
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
The last request received and responded to
configserver/src/test/java/com/yahoo/vespa/config/server/rpc/MockRpcServer.java