@Override
  public String lookup(LogEvent event, String key) {
    return lookup(key);
  }
A log4j plugin that substitutes {@code $${uptime:now}} pattern with the elapsed time of the program in {@code
H:MM:SS} form.
<p>
log4j properties file needs to include {@code packages=com.onthegomap.planetiler.util.log4j} to look in this package
for plugins.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/log4j/ElapsedTimeLookupPlugin.java