title: Akka child actors return a void type and refuse to send messages
body: <p>I was learnning Akka Typed Actor library and tried to send a message to all child actors of a particular actor, using <code>this.getContext().getChildren()</code>. But it returns a <code>Void</code> type and not the type I initially created the child actors with -&gt; hence I could not send any type of message to the children.</p>
  <p>The workaround I did is to simply store the children in a hashmap at the time of creation. But this is not a scalable one.</p>
  <p><strong>How can I achieve this? especially under distributed scenario?</strong></p>
  <pre><code>        .onMessage(GetPosition.class, message -&gt; {
  
              // whenever I send a GetPosition() message to myself,
              // I get that reminder and send an AskPosition to all workers
  
              while (results.keySet().size() &lt; 10) {
                  // while not finished, ask for positions from child actors
  
                  // This is not working
                  this.getContext().getChildren().forEach(child -&gt; {
                      child.tell(&quot;this is a void class, so I cannot send any message to children&quot;);
                  });
  
                  // WORKAROUND:
                  // get child  actors from hashmap (hashmap lambda has 2 things in it -&gt; bi-consumer)
                  racers.forEach((id, actor) -&gt; actor.tell(new RacerBehavior.AskPosition(this.getContext().getSelf())));
              }
  
              return this;
          })
  </code></pre>