title: Firestore how to clearPersistence()
body: <p>I need to clear current user data completely once user logout.
  Therefore I use clearPersistence() function.
  It need to run terminate() before clearPersistence().</p>
  
  <pre><code> this.afs.firestore.terminate().then(() =&gt; {
        this.afs.firestore.clearPersistence().then(() =&gt; {
        });
  });
  </code></pre>
  
  <p>After run below above to clear firestore local cache, I receive this error.</p>
  
  <p><code>FirebaseError: The client has already been terminated.</code></p>
  
  <p>Any advice how to re initialise firestore instance or any better way to achieve?
  Thanks.</p>