package overflow_subscriber import "fmt" type ChannelExistError struct { Channel string } // Error returns the formatted configuration error. func (cee ChannelExistError) Error() string { return fmt.Sprintf("Subscriber: Channel[%q] is already subscribed.", cee.Channel) } type ChannelIsNotExistError struct { Channel string } // Error returns the formatted configuration error. func (cinee ChannelIsNotExistError) Error() string { return fmt.Sprintf("Subscriber: Channel[%q] is not subscribed.", cinee.Channel) } type Subscriber interface { Start() error Stop() Subscribe(h SubscriberHandler) error Unsubscribe(h SubscriberHandler) error }