数据结构
type Topic struct {
// 64bit atomic vars need to be first for proper alignment on 32bit platforms
messageCount uint64 //消息数量
messageBytes uint64 // 消息字节数
sync.RWMutex
name string //topic 名字
channelMapmap [string]*Channel //关联的channel组
backend BackendQueue //磁盘队列
memoryMsgChanchan *Message //内存队列
startChan chan int // 开始标志
exitChan chan int // 结束标志
channelUpdateChanchan int //关联的channel增加或者减少, 需要通知更新
waitGroup util.WaitGroupWrapper
exitFlag int32
idFactory *guidFactory
ephemeral bool
deleteCallbackfunc(*Topic)
deleter sync.Once
paused int32
pauseChan chan int
ctx *context
}
