You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: server_entrypoint_tcp_http3.go
    path of file: ./repos/traefik/pkg/server
    
    the code of the file until where you have to start completion: package server

import (
	"context"
	"crypto/tls"
	"errors"
	"fmt"
	"net"
	"net/http"
	"sync"

	"github.com/quic-go/quic-go/http3"
	"github.com/rs/zerolog/log"
	"github.com/traefik/traefik/v3/pkg/config/static"
	tcprouter "github.com/traefik/traefik/v3/pkg/server/router/tcp"
)

type http3server struct {
	*http3.Server

	http3conn net.PacketConn

	lock   sync.RWMutex
	getter func(info *tls.ClientHelloInfo) (*tls.Config, error)
}

func newHTTP3Server(ctx context.Context, configuration *static.EntryPoint, httpsServer *httpServer) (*
    
func newHTTP3Server(ctx context.Context, configuration *static.EntryPoint, httpsServer *httpServer) (*http3server, error) {
	if configuration.HTTP3 == nil {
		return nil, nil
	}

	if configuration.HTTP3.AdvertisedPort < 0 {
		return nil, errors.New("advertised port must be greater than or equal to zero")
	}

	listenConfig := newListenConfig(configuration)
	conn, err := listenConfig.ListenPacket(ctx, "udp", configuration.GetAddress())
	if err != nil {
		return nil, fmt.Errorf("starting listener: %w", err)
	}

	h3 := &http3server{
		http3conn: conn,
		getter: func(info *tls.ClientHelloInfo) (*tls.Config, error) {
			return nil, errors.New("no tls config")
		},
	}

	h3.Server = &http3.Server{
		Addr:      configuration.GetAddress(),
		Port:      configuration.HTTP3.AdvertisedPort,
		Handler:   httpsServer.Server.(*http.Server).Handler,
		TLSConfig: &tls.Config{GetConfigForClient: h3.getGetConfigForClient},
	}

	previousHandler := httpsServer.Server.(*http.Server).Handler

	httpsServer.Server.(*http.Server).Handler = http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		if err := h3.Server.SetQuicHeaders(rw.Header()); err != nil {
			log.Ctx(ctx).Error().Err(err).Msg("Failed to set HTTP3 headers")
		}

		previousHandler.ServeHTTP(rw, req)
	})

	return h3, nil
}