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: race_test.go
    path of file: ./repos/protobuf-go/internal/testprotos/race
    
    the code of the file until where you have to start completion: // Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package race_test

import (
	"sync"
	"testing"

	"google.golang.org/protobuf/proto"

	epb "google.golang.org/protobuf/internal/testprotos/race/extender"
	mpb "google.golang.org/protobuf/internal/testprotos/race/message"
)

// There must be no other test in this package as we are testing global
// initialization which only happens 
    
func TestConcurrentInitialization(t *testing.T) {
	var wg sync.WaitGroup
	wg.Add(2)
	go func() {
		defer wg.Done()
		m := &mpb.MyMessage{
			I32: proto.Int32(int32(42)),
		}
		// This initializes the descriptor.
		_, err := proto.Marshal(m)
		if err != nil {
			t.Errorf("proto.Marshal(): %v", err)
		}
	}()
	go func() {
		defer wg.Done()
		m := &epb.OtherMessage{
			I32: proto.Int32(int32(42)),
		}
		// This initializes the descriptor including the extension.
		_, err := proto.Marshal(m)
		if err != nil {
			t.Errorf("proto.Marshal(): %v", err)
		}
	}()
	wg.Wait()
}