synchronized int queueSize() {
        int sum = 0;
        for (int cnt : counts) {
            sum += cnt;
        }
        return sum;
    }
@author <a href="mailto:havardpe@yahoo-inc.com">Haavard Pettersen</a>
@author Simon Thoresen Hult
jdisc_core/src/main/java/com/yahoo/jdisc/core/ScheduledQueue.java