func (a *Announce) Close() {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.close()
}
func (a *Announce) Close() {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.close()
}
func ( a * Announce ) Close ( ) { a . mu . Lock ( ) defer a . mu . Unlock ( ) a . close ( ) }
// Stop the announce.
Stop the announce .