docs: public Channel onFindChannel(FindChannelEvent event) {
          Assert.notNull(event);
          Long channelId = event.getChannelId();
          Long pipelineId = event.getPipelineId();
          Channel channel = null;
          if (channelId != null) {
              channel = channelService.findById(channelId);
          } else {
              Assert.notNull(pipelineId);
              channel = channelService.findByPipelineId(pipelineId);
          }
  
          return channel;
      }