ash2k

$ go build --race ./main.go
$ ./main                   
5
==================
WARNING: DATA RACE
Read by goroutine 7:
  runtime.mapaccess1_fast64()
      /usr/local/Cellar/go/1.6/libexec/src/runtime/hashmap_fast.go:103 +0x0
  main.main.func2()
      /Users/ash2k/sources/gotest2/main.go:18 +0x4e

ash2k

$ go build --race ./no_race.go
$ ./no_race                   
1
1
1
1
1
1
1
1

ash2k

var sink string
var x string = "somestring"

// BenchmarkPrint-8        10000000               198 ns/op              32 B/op          2 allocs/op
func BenchmarkPrint(b *testing.B) {
	b.ReportAllocs()
	var s string
	for i := 0; i < b.N; i++ {
		s = fmt.Sprintf("abc.%s", x)
	}

ash2k

func startStopServer(ctx context.Context, srv *http.Server, shutdownTimeout time.Duration) error {
	var wg sync.WaitGroup
	defer wg.Wait() // wait for goroutine to shutdown active connections
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()
	wg.Add(1)
	go func() {
		defer wg.Done()
		<-ctx.Done()
		c, cancel := context.WithTimeout(context.Background(), shutdownTimeout)