code: private static void appendFunction(StringBuilder message, LogRecord event)
      {
          final String clazz = event.getSourceClassName();
          if (clazz != null)
          {
              message.append(IN).append(clazz);
          }
  
          final String function = event.getSourceMethodName();
          if (function != null)
          {
              message.append(AT).append(function).append(Constant.DOUBLE_DOT);
          }
      }
docs: Append function location.
  
  @param message The message builder.
  @param event The log record.