public String toString() {
            StringBuilder buffer = new StringBuilder();
            int preLen;
            buffer.append(name).append("(").append("QueryProcessing(");
            preLen = buffer.length();
            for (Map.Entry<Activity, Long> m : invoking.entrySet()) {
                activityRepr(buffer, preLen, m);
            }
            buffer.append("), ResultProcessing(");
            preLen = buffer.length();
            for (Map.Entry<Activity, Long> m : returning.entrySet()) {
                activityRepr(buffer, preLen, m);
            }
            buffer.append("))");
            return buffer.toString();
        }
A container for storing time stamps throughout the lifetime of an Execution instance.

<p>Check state both when entering and exiting, to allow for arbitrary
new queries anywhere inside a search chain.

@author Steinar Knutsen
container-search/src/main/java/com/yahoo/search/statistics/TimeTracker.java