code: func NewTCPStatCollector() (Collector, error) {
  	return &tcpStatCollector{
  		desc: typedDesc{prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, "tcp", "connection_states"),
  			"Number of connection states.",
  			[]string{"state"}, nil,
  		), prometheus.GaugeValue},
  	}, nil
  }
docs: // NewTCPStatCollector returns a new Collector exposing network stats.