code: func NewDialFunc(optFuncs ...dialerOpt) func(string, string) (net.Conn, error) {
  	dialContextFunc := NewDialContextFunc(optFuncs...)
  	return func(network string, addr string) (net.Conn, error) {
  		return dialContextFunc(context.TODO(), network, addr)
  	}
  }
docs: // NewDialFunc returns a `Dial` function that tracks outbound connections.
  // The signature is compatible with `http.Tranport.Dial` and is meant to be used there for Go < 1.7.