title: Is this logging blocking?
body: <p>I have read that AkkaLogging is async and directly using slf4j is blocking. Consider the below code:</p>
  
  <p>application.conf:</p>
  
  <pre><code>akka {
    loggers = ["akka.event.slf4j.Slf4jLogger"]
  }
  </code></pre>
  
  <p>logback.xml:</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;appender name="InfoFile" class="ch.qos.logback.core.FileAppender"&gt;
  &lt;file&gt;Testing.log&lt;/file&gt;
      &lt;append&gt;true&lt;/append&gt;
      &lt;encoder&gt;
          &lt;pattern&gt;%msg%n&lt;/pattern&gt;
      &lt;/encoder&gt;
  &lt;/appender&gt;
  
  &lt;root level="INFO"&gt;
  &lt;appender-ref ref="InfoFile" /&gt;
  &lt;/root&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Log statements:</p>
  
  <pre><code>  log.info("Sample logging")
  </code></pre>
  
  <p>Will this logging code be still blocking?If so, does it mean there is no way to achieve non blocking file logging in akka? </p>