title: Log4j2 custom layout
body: <p>I am using Log4j2 with a <code>PatternLayout</code>.  Is it possible to write my own <code>Layout</code> that extends <code>AbstractStringLayout</code>, so that I can customize my output message?</p>
  
  <p>I have read the docs but I only see variations of layouts - no custom one.</p>
  
  <p><a href="https://logging.apache.org/log4j/2.x/manual/layouts.html" rel="noreferrer">https://logging.apache.org/log4j/2.x/manual/layouts.html</a></p>