code: @Override
  	public void format(final StringBuffer sbuf, final LoggingEvent event) {
  		for (int i = 0; i < patternConverters.length; i++) {
  			final int startField = sbuf.length();
  			patternConverters[i].format(event, sbuf);
  			patternFields[i].format(startField, sbuf);
  		}
  	}
docs: Format event to string buffer.
  
  @param sbuf
  string buffer to receive formatted event, may not be null.
  @param event
  event to format, may not be null.