@Override
    public void pingIterationCompleted() {
        pingIterationCompleted(monitoredGroups);
    }
Update statistics after a round of issuing pings.
Note that this doesn't wait for pings to return, so it will typically accumulate data from
last rounds pinging, or potentially (although unlikely) some combination of new and old data.
container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/SearchCluster.java