event

type Emitter struct {
	// contains filtered or unexported fields
}

type IEmitter interface {
	On(topic string, fn interface{})
	OnSync(topic string, fn interface{})
	Once(topic string, fn interface{})
	OnceSync(topic string, fn interface{})
	Off(topic string, fn interface{})
	Emit(topic string, args ...interface{})
}