func (s *Sentinel) close() {
	if s.pools != nil {
		for _, pool := range s.pools {
			pool.Close()
		}
	}
	s.pools = nil
}
func (s *Sentinel) close() {
	if s.pools != nil {
		for _, pool := range s.pools {
			pool.Close()
		}
	}
	s.pools = nil
}
func ( s * Sentinel ) close ( ) { if s . pools != nil { for _ , pool := range s . pools { pool . Close ( ) } } s . pools = nil }
// close connection pool to Sentinel.
// Lock must be hold by caller.
close connection pool to Sentinel . Lock must be hold by caller .