title: Catch error but continu iterating the list
body: <p>I have a function in Kotlin which is doing this :</p>
  
  <pre><code> fun getItemByIds(ids: List&lt;Long&gt;): Single&lt;List&lt;Item&gt;&gt; {
      return Flowable.fromIterable(ids)
          .flatMapSingle { getItem(it) }
          .toList()
    }
  </code></pre>
  
  <p>This working well but in case of an error generated by the getItem such as a http error 404, the code is not continuing to iterate. </p>
  
  <p>getItem is returning a <code>Single&lt;&gt;</code> but in case of http error, I return <code>Single.error(it)</code>.</p>
  
  <p>What I am looking to do is make sure that the list is still build and in case of an error, I am just dismissing the error and build the list with the item who generate the error.</p>
  
  <p>Any idea ?</p>