code: protected void afterStartEventParser(CanalEventParser eventParser) {
          // 读取一下历史订阅的filter信息
          List<ClientIdentity> clientIdentitys = metaManager.listAllSubscribeInfo(destination);
          for (ClientIdentity clientIdentity : clientIdentitys) {
              subscribeChange(clientIdentity);
          }
      }
docs: around event parser, default impl