Bug description

PostExecutionStartEvent and PostExecutionStopEvent both contain a request ID. Users should be able to uniquely identify the events based on the request Id and correlate the start/stop event pairs for processing.

In our performance testing, we found out that sometimes different tasks had same request ID. Here is a snapshot of the events:

These events have the same id but from the call stacks of the Start events, they are clearly not from the same task.