title: How to get Cognito Identity ID given the Cognito User Pool ID?
body: <p>In <a href="https://aws-amplify.github.io/docs/js/storage#get" rel="noreferrer">AWS Amplify's Storage Documentation</a>, there's a section on how to get other users' objects...</p>
  
  <pre><code>Storage.get('test.txt', { 
      level: 'protected', 
      identityId: 'xxxxxxx' // the identityId of that user
  })
  </code></pre>
  
  <p>Where can I get the identityId of another user? </p>
  
  <p>I can only query for the Cognito User Pool Id of users. Is there a way to map the User Pool Id to the Identity Id?</p>