Trigger 2nd form submit click after another Observable is done
<p>Here is the simple procedure we would like to do with and only with use of <code>RXJS Observables</code>:</p>

<ol>
<li>Click Login button (form with username &amp; password). <code>Observable.fromEvent</code> is bound with our form.</li>
<li>After submitting the form, call <code>loginUser()</code>, which sends http request to server and returns Observable.</li>
<li>if HTTP request is in progress: Clicking login button should not trigger another login request.</li>
<li>if HTTP request is NOT in progress: Clicking login button should trigger another login request.</li>
</ol>

<p><code>take(1)</code>, <code>takeUntil()</code>, <code>takeLast()</code> didn't helped us. So what is the proper way to stop the login executing if we click the Login button 5-times in 500ms and make it available again, after <code>loginUser()</code> completes?</p>

<p>This should be doable with Observables only, the only problem is the last part, described in previous sentence.</p>

<p>Thank you all for your help!</p>