String resetAndReport(String eventName) {
      long total = this.total.getAndSet(0);
      long overhead = this.overhead.getAndSet(0);
      long count = this.count.getAndSet(0);
      NumberFormat format = NumberFormat.getInstance(Locale.US);
      return format.format(count) + " " + eventName + " calls, " +
             format.format(overhead) + " overhead ns" +
             (count == 0 && total == 0 ? "" : " (" + StringUtil.join(Arrays.asList(
               count == 0 ? null : format.format(overhead / count) + " ns/call",
               total == 0 ? null : String.format("%.2f", overhead / (double)(total / 100)) + " %"
             ), ", ") + ")");
    }
String resetAndReport(String eventName)