title: How do we convert a Mono<List<Type>> to a Flux<Type>
body: <p>Using spring 5, with reactor we have the following need.</p>
  
  <pre><code>Mono&lt;TheResponseObject&gt; getItemById(String id){
      return webClient.uri('/foo').retrieve().bodyToMono(TheResponseObject)
  }
  
  Mono&lt;List&lt;String&gt;&gt; getItemIds(){
      return webClient.uri('/ids').retrieve().bodyToMono(List)
  }
  
  Mono&lt;RichResonseObject&gt; getRichResponse(){
      Mono&lt;List&gt; listOfIds = Mono.getItemIds()
      listOfIds.each({ String id -&gt;
          ? &lt;&lt; getItemById(id) //&lt;&lt;&lt; how do we convert a list of ids in a Mono to a Flux
      })
      Mono&lt;Object&gt; someOtherMono = getOtherMono()
      return Mono.zip((? as Flux).collectAsList(), someOtherMono).map({
          Tuple2&lt;List, Object&gt; pair -&gt;
          return new RichResonseObject(pair.getT1(), pair.getT2())
      }).cast(RichResonseObject)
  }
  </code></pre>
  
  <blockquote>
    <p>What approaches are possible to convert a Mono&lt;List&lt;String&gt;&gt; to a Flux&lt;String&gt;?</p>
  </blockquote>