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: echo.go
    path of file: ./repos/quic-go/example/echo
    
    the code of the file until where you have to start completion: package main

import (
	"context"
	"crypto/rand"
	"crypto/rsa"
	"crypto/tls"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"io"
	"log"
	"math/big"

	"github.com/quic-go/quic-go"
)

const addr = "localhost:4242"

const message = "foobar"

// We start a server echoing data on the first stream the client opens,
// then connect with a client, send the messa
    
func clientMain() error {
	tlsConf := &tls.Config{
		InsecureSkipVerify: true,
		NextProtos:         []string{"quic-echo-example"},
	}
	conn, err := quic.DialAddr(context.Background(), addr, tlsConf, nil)
	if err != nil {
		return err
	}
	defer conn.CloseWithError(0, "")

	stream, err := conn.OpenStreamSync(context.Background())
	if err != nil {
		return err
	}
	defer stream.Close()

	fmt.Printf("Client: Sending '%s'\n", message)
	_, err = stream.Write([]byte(message))
	if err != nil {
		return err
	}

	buf := make([]byte, len(message))
	_, err = io.ReadFull(stream, buf)
	if err != nil {
		return err
	}
	fmt.Printf("Client: Got '%s'\n", buf)

	return nil
}