public long first() {
        long first = Long.MAX_VALUE;
        for (TimeTracker track : tracks) {
            if (track.first() != 0)
                first = Math.min(first, track.first());
        }
        if (first == Long.MAX_VALUE) return 0L;
        return first;
    }
Time stamp of start of the first event registered, or 0 if none are regiustered.
container-search/src/main/java/com/yahoo/search/statistics/ElapsedTime.java