title: Webflux collect errors from list?
body: <p>I have a <code>List&lt;String&gt; myList</code>. The code looks like:</p>
  <pre><code>Flux.fromIterable(myList)
    .distinct()
    .flatMap(id -&gt; mysvc.getItem(id)
          .switchIfEmpty(Mono.error(...))))
  </code></pre>
  <p>Note that mysvc is returning a <code>Mono&lt;Item&gt;</code> and the .switchIfEmpty is attached to THAT CALL, NOT the flatmap as mysvc will return a <code>Mono.empty()</code> if id is invalid.</p>
  <p>Right now, it is throwing an error if an id is invalid as expected, but it throws them one at a time. If you have 2 errors, you'll only see the first one until you fix it, and then you'll see the next one and so on.</p>
  <p>Ideally, I'd like to somehow collect all the bad ids and display a single error message otherwise return the <code>Flux&lt;Item&gt;</code>.</p>