code: @Override
      public void startEvent(String eventName) {
          /* This will overwrite past events */
          eventsBeingProfiled.put // ignoring the wall clock time
              (eventName, TimingInfo.startTimingFullSupport(System.nanoTime()));
      }
docs: Start an event which will be timed. The startTime and endTime are added
  to timingInfo only after endEvent is called. For every startEvent there
  should be a corresponding endEvent. If you start the same event without
  ending it, this will overwrite the old event. i.e. There is no support
  for recursive events yet. Having said that, if you start and end an event
  in that sequence multiple times, all events are logged in timingInfo in
  that order.
  
  This feature is enabled if the system property
  "com.ibm.cloud.objectstorage.sdk.enableRuntimeProfiling" is set, or if a
  {@link RequestMetricCollector} is in use either at the request, web service
  client, or AWS SDK level.
  
  @param eventName
  - The name of the event to start
  
  @see AwsSdkMetrics