t.Fatalf("Wait succeeded, want SIGABRT")
	}
	ee, ok := err.(*exec.ExitError)
	if !ok {
		t.Fatalf("Wait err got %T %v, want exec.ExitError", ee, ee)
	}
	ws, ok := ee.Sys().(syscall.WaitStatus)
	if !ok {
		t.Fatalf("Sys got %T %v, want syscall.WaitStatus", ee.Sys(), ee.Sys())
	}
	if ws.Signal() != syscall.SIGABRT {
		t.Fatalf("Signal got %d want SIGABRT", ws.Signal())
	}
	if !ws.CoreDump() {

	defer dnsWaitGroup.Wait()

	txts, err := LookupTXT("golang.rsc.io")
	if err != nil {
		t.Fatal(err)
	}
	slices.Sort(txts)
	want := []string{
		strings.Repeat("abcdefghijklmnopqrstuvwxyABCDEFGHJIKLMNOPQRSTUVWXY", 10),
		"gophers rule",
	}
	if !reflect.DeepEqual(txts, want) {
		t.Fatalf("LookupTXT golang.rsc.io incorrect\nhave %q\nwant %q", txts, want)
	}
}

	}
	t.Logf("WriteString(%q) = <nil>", part1)

	wait := mustBlock(t, "Read", func() {
		b, err := lockedfile.Read(path)
		if err != nil {
			t.Errorf("Read: %v", err)
			return
		}

		const want = part1 + part2
		got := string(b)
		if got == want {
			t.Logf("Read(_) = %q", got)
		} else {
			t.Errorf("Read(_) = %q, _; want %q", got, want)
		}
	})

	_, err = f.WriteString(part2)

	n := 2
	running := make(chan bool, n)
	awake := make(chan bool, n)
	for i := 0; i < n; i++ {
		go func() {
			m.Lock()
			running <- true
			c.Wait()
			awake <- true
			m.Unlock()
		}()
	}
	for i := 0; i < n; i++ {
		<-running // Wait for everyone to run.
	}
	for n > 0 {
		select {
		case <-awake:
			t.Fatal("goroutine not asleep")
		default:
		}
		m.Lock()
		c.Signal()
		m.Unlock()

			sum += i
		}
		fmt.Println("Computed once:", sum)
		return sum
	})
	done := make(chan bool)
	for i := 0; i < 10; i++ {
		go func() {
			const want = 499500
			got := once()
			if got != want {
				fmt.Println("want", want, "got", got)
			}
			done <- true
		}()
	}
	for i := 0; i < 10; i++ {
		<-done
	}
	// Output:
	// Computed once: 499500
}

		if len(events) == 0 {
			return
		}
		select {
		case e := <-fx.Events:
			found := false
			for i, want := range events {
				if e.Type == want.Type &&
					(want.ID == "" || e.ID == want.ID) &&
					(want.Namespace == "" || want.Namespace == e.Namespace) &&
					(want.EndpointCount == 0 || want.EndpointCount == len(e.Endpoints)) {
					// Matched - delete event from desired
					events = slices.Delete(events, i)

				k, v := next[int](), next[int32]()
				m[k] = v
				c.Put(k, v)
			}
			barrier.Done()
			barrier.Wait()

			for k, v := range m {
				if cv := c.Get(k); cv != v {
					t.Errorf("c.Get(%v) = %v, want %v", str(k), str(cv), str(v))
					atomic.AddInt32(&lost, +1)
				}
			}
		}()
	}
	wg.Wait()
	if lost != 0 {
		t.Errorf("lost %d entries", lost)
	}

	f(t, c1, c2)
}

// testBasicIO tests that the data sent on c1 is properly received on c2.
func testBasicIO(t *testing.T, c1, c2 net.Conn) {
	want := make([]byte, 1<<20)
	rand.New(rand.NewSource(0)).Read(want)

	dataCh := make(chan []byte)
	go func() {
		rd := bytes.NewReader(want)
		if err := chunkedCopy(c1, rd); err != nil {
			t.Errorf("unexpected c1.Write error: %v", err)
		}
		if err := c1.Close(); err != nil {

			continue
		}
		if tt.wantpos != 0 && tt.wantpos != pos {
			t.Errorf("%d. pos = %d, want %d", i, pos, tt.wantpos)
		}
		buf := make([]byte, tt.n)
		n, err := r.Read(buf)
		if err != tt.readerr {
			t.Errorf("%d. read = %v; want %v", i, err, tt.readerr)
			continue
		}
		got := string(buf[:n])
		if got != tt.want {
			t.Errorf("%d. got %q; want %q", i, got, tt.want)
		}
	}

	}
	transformer := &envelopeTransformer{}

	want := sets.NewInt()
	startCh := make(chan struct{})
	wg := sync.WaitGroup{}
	for i := 0; i < 100; i++ {
		want.Insert(i + 1)
		k := fmt.Sprintf("key-%d", i)
		wg.Add(1)
		go func(key string) {
			defer wg.Done()
			<-startCh
			cache.set([]byte(key), transformer)
		}(k)
	}
	close(startCh)
	wg.Wait()

	got := sets.NewInt()