title: Log4j2 RollingFile Appender - add custom info at the start of each logfile
body: <p>Using log4j2 (beta9) with java 1.7.</p>
  
  <p>My complete log4j2.xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;Configuration&gt;
    &lt;Properties&gt;
      &lt;Property name="projectPrefix"&gt;Tts&lt;/Property&gt;
      &lt;Property name="rawPattern"&gt;%d %-5p [%t] %C{2} (%F:%L) - %m%n&lt;/Property&gt;
      &lt;Property name="coloredPattern"&gt;%d %highlight{%-5p}{FATAL=bright red, ERROR=red, WARN=yellow, INFO=cyan, DEBUG=green, TRACE=bright blue} %style{[%t] %C{2} (%F:%L) -}{bright,black} %m%n&lt;/Property&gt;
      &lt;Property name="fileName"&gt;Log/${projectPrefix}.log&lt;/Property&gt;
      &lt;Property name="filePattern"&gt;Log/${projectPrefix}-%i.log&lt;/Property&gt;
    &lt;/Properties&gt;
    &lt;Appenders&gt;
      &lt;Console name="Stdout" target="SYSTEM_OUT"&gt;
        &lt;PatternLayout pattern="${coloredPattern}"/&gt;
      &lt;/Console&gt;
      &lt;RollingFile name="Logfile" fileName="${fileName}" filePattern="${filePattern}"&gt;
        &lt;PatternLayout pattern="${rawPattern}"/&gt;
        &lt;Policies&gt;
          &lt;SizeBasedTriggeringPolicy size="16 MB"/&gt;
        &lt;/Policies&gt;
        &lt;DefaultRolloverStrategy fileIndex="min" max="16"/&gt;
      &lt;/RollingFile&gt;
    &lt;/Appenders&gt;
    &lt;Loggers&gt;
      &lt;Root level="info"&gt;
        &lt;AppenderRef ref="Stdout"/&gt;
        &lt;AppenderRef ref="Logfile"/&gt;
      &lt;/Root&gt;
    &lt;/Loggers&gt;
  &lt;/Configuration&gt;
  </code></pre>
  
  <p>I want to add some custom info at the top of each logfile, like the version string of my application, the application uptime and the system uptime. And even writing some »bye, bye / eof« to the bottom of the just closed logfile would also be fine.</p>
  
  <p>Is there something like a hook or callback to get notified when the RollingFileAppander has created a new file, so that I can put my things at first into these new logfile (or any other suggestion)?</p>