subchannel.go
func Isolated(s *SubChannel) {
	s.Lock()
	s.peers = s.topChannel.peers.newSibling()
	s.peers.SetStrategy(newLeastPendingCalculator())
	s.Unlock()
}
func Isolated(s *SubChannel) {
	s.Lock()
	s.peers = s.topChannel.peers.newSibling()
	s.peers.SetStrategy(newLeastPendingCalculator())
	s.Unlock()
}
// Isolated is a SubChannelOption that creates an isolated subchannel.