code: public void deltaTotalUsageTime(long delta)
     {
        if (enabled.get() && delta > 0)
        {
           totalUsageTime.addAndGet(delta);
           totalUsageTimeInvocations.incrementAndGet();
  
           if (delta > maxUsageTime.get())
              maxUsageTime.set(delta);
        }
     }
docs: Add delta to total usage time
  @param delta The value