channel.go
func (ch *Channel) StatsTags() map[string]string {
	m := make(map[string]string)
	for k, v := range ch.commonStatsTags {
		m[k] = v
	}
	return m
}
func (ch *Channel) StatsTags() map[string]string {
	m := make(map[string]string)
	for k, v := range ch.commonStatsTags {
		m[k] = v
	}
	return m
}
// StatsTags returns the common tags that should be used when reporting stats.
// It returns a new map for each call.