t.Fatalf("unable to create listener. %v", err)
	}
	defer l.Close()
	serverAddr := l.Addr().String()

	tcpListener, ok := l.(*net.TCPListener)
	if !ok {
		t.Fatalf("failed to assert to net.TCPListener")
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.Done()

		tcpConn, terr := tcpListener.AcceptTCP()
		if terr != nil {
			t.Errorf("failed to accept new connection. %v", terr)
			return
		}

const (
	// HTTPListener identifies a listener as being of HTTP type by the presence of an HTTP connection manager filter
	HTTPListener = wellknown.HTTPConnectionManager

	// TCPListener identifies a listener as being of TCP type by the presence of TCP proxy filter
	TCPListener = wellknown.TCPProxy

	IPMatcher = "type.googleapis.com/xds.type.matcher.v3.IPMatcher"
)

		}
	}

	// Closure to handle TCPListener until done channel is closed.
	handleListener := func(idx int, listener net.Listener) {
		for {
			conn, err := listener.Accept()
			send(acceptResult{conn, err, idx})
		}
	}

	// Start separate goroutine for each TCP listener to handle connection.
	for idx, tcpListener := range listener.listeners {
		go handleListener(idx, tcpListener)
	}
}