title: CompletableFuture wrapper
body: <p>I have async method</p>
  
  <pre><code>asyncClass.getChild("test", listChild -&gt; {
    if (listChild.isOk()) {
    List&lt;String&gt; list = listChild.isSuccess().getData()
    }
    return null;
  });
  </code></pre>
  
  <p>How I can wrap this async call in CompletableFuture?</p>
  
  <pre><code>final CompletableFuture&lt;List&lt;String&gt;&gt; future = new CompletableFuture&lt;&gt;();
  asyncClass.getChild("test", listChild -&gt; {
    if (listChild.isOk()) {
      future.complete(listChild.isSuccess().getData());
    }
    return null;
  });
  return future;
  </code></pre>
  
  <p>Everything works fine, but I want everything to work in a separate thread calls</p>
  
  <pre><code>interface AsyncFS {
      fun getChild(path: String, onResult: (Result&lt;List&lt;String&gt;&gt;) -&gt; Unit)
  }
  </code></pre>