title: How to use rate limit in azure api management by using custom apiKey other than subscripon id?
body: <p>It is easy to rate limit the api by using, </p>
  
  <pre><code>&lt;rate-limit-by-key calls="3" renewal-period="15" counter-key="@(context.Subscription.Id)" /&gt;
  </code></pre>
  
  <p>But i need to rate limit the api by using a apiKey send as a request parameter.</p>