code: public String format(final LoggingEvent event) {
  		final StringBuffer buf = new StringBuffer();
  		for (PatternConverter c = head; c != null; c = c.next) {
  			c.format(buf, event);
  		}
  		return buf.toString();
  	}
docs: Formats a logging event to a writer.
  
  @param event
  logging event to be formatted.