go/state.go
func (s *State) NumConnections() int {
	s.connMut.Lock()
	n := len(s.conns)
	s.connMut.Unlock()
	return n
}
func (s *State) NumConnections() int {
	s.connMut.Lock()
	n := len(s.conns)
	s.connMut.Unlock()
	return n
}
//NumConnections currently active