# Functions
NewRssDomain 新建RssDomain，调用方保证单例模式.
# Structs
RssClientView 频道视图.
RssContent 订阅的RSS频道的推送信息.
RssHubClient rss hub client (http).
RssSource RSS频道.
RssSubscribe 订阅关系表：群组-RSS频道.
# Interfaces
RepoContent RSS 推送信息存储接口.
RepoMultiQuery 多表查询接口.
RepoSource RSS 订阅源存储接口.
RepoStorage 定义RepoStorage接口.
RepoSubscribe RSS 订阅存储接口.
RssDomain RssRepo定义.