title: Request Identifier in header to detect replay of a request
body: <p>I have seen http headers like x-ms-tracking-id which would be a unique identifier  when sending a (post/put/patch) request to a REST API. The server would detect the tracking id header and in case if it was a duplicate, the server would reject the request. This provides for idempotency for clients and help in timeout scenarios.</p>
  
  <p>Question is: What are some good patterns to implement above in asp net Web API? Which storage to use to make this happen without significant perf impact?</p>
  
  <p>The tracking-id obviously has to be stored and every request(post/put/patch) incurs the cost of lookup which has a perf impact.</p>