How to use with QUIC without running into DATAGRAM frame too large error

[LeonardWalter]

Hi,
I am trying to build a DoQ client combined with a masque proxy.
Currently I am using this code to connect to my DoQ server at myurl:8853:

	template := uritemplate.MustNew("https://myurl.org:9443/masque?h={target_host}&p={target_port}")
	target := "myurl.org:8853"

	raddr, err := net.ResolveUDPAddr("udp", target)
	if err != nil {
		log.Fatalf("failed to resolve udp addr: %v", err)
		return
	}

	cl := masque.Client{
		QUICConfig: &quic.Config{
			EnableDatagrams:   true,
			InitialPacketSize: 1350,
		},
	}

	pconn, _, err := cl.Dial(context.Background(), template, raddr)
	if err != nil {
		log.Fatalf("failed to dial masque proxy: %v", err)
		return
	}

	qc := new(quic.Config)
	qc.DisablePathMTUDiscovery = true
	tc := new(tls.Config)
	tc.ServerName = "myurl.org"
	tc.NextProtos = []string{"doq"}

	earlyConn, err := quic.DialEarly(context.Background(), pconn, raddr, tc, qc)
	if err != nil {
		log.Fatalf("failed to dial target via masque proxy: %v", err)
		return
	}

Everything seems to work fine with the client, but on the proxy I always receive following error, which causes the quic.DialEarly to fail.
2024/12/05 13:57:38 proxying receive side to [2a02:****:5d33]:8853 failed: DATAGRAM frame too large

I already tried different quic.Config InitialPacketSize values for both inner quic and outer masque stream but I cant get it to work.