t.Errorf("mu2.Lock: %v", err)
			return
		}
		t.Logf("unlock2, _ := mu2.Lock()")
		t.Logf("unlock2()")
		unlock2()
	})

	t.Logf("unlock()")
	unlock()
	wait(t)
}

func TestReadWaitsForLock(t *testing.T) {
	t.Parallel()

	dir, remove := mustTempDir(t)
	defer remove()

	path := filepath.Join(dir, "timestamp.txt")

	f, err := lockedfile.Create(path)
	if err != nil {