servers/listener.go
func (s *Listener) SetAddr(addr string) {
	if s.Server.Addr == "" {
		s.Server.Addr = addr
	}
}
func (s *Listener) SetAddr(addr string) {
	if s.Server.Addr == "" {
		s.Server.Addr = addr
	}
}
// SetAddr sets the servers address, if it hasn't already been set