public boolean isLastReceivedPong(long pingId ) {
        long last = lastPong.get();
        while ((pingId > last) && ! lastPong.compareAndSet(last, pingId)) {
            last = lastPong.get();
        }
        return last < pingId;
    }
Checks if this pong is received in line and accepted, or out of band and should be ignored.
container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/Node.java