GetOrRegisterChannel tries to get the StatChannel first.

GetOrRegisterCounter tries to get the StatCounter first.

ManagerType returns the type of Manager interface.

SubscribeRunnableChannel subscribes the channel and starts it if there is first subscriber coming.

UnsubscribeClosableChannel unsubscribes the channel and close it if there is no more subscriber.

NoopManager is an implementation of Manager, which doesn't has actual functionalities.

Channel is the interface for stats channel.

Counter is the interface for stats counters.

Manager is the interface for stats manager.