code: @Override
      public int appendLoopOnAppenders(LoggingEvent event) {
          int size = 0;
          Appender appender;
          if (appenderList != null) {
              size = appenderList.size();
              Iterator<Appender> it = appenderList.iterator();
              while (it.hasNext()) {
                  appender = (Appender) it.next();
                  appender.doAppend(event);
              }
          }
          return size;
      }
docs: /*
  (non-Javadoc)
  
  @see
  org.apache.log4j.helpers.AppenderAttachableImpl#appendLoopOnAppenders
  (org.apache.log4j.spi.LoggingEvent)