Timeout() bool
	})
	if !ok {
		t.Fatal("DeadlineExceeded does not support Timeout interface")
	}
	if !i.Timeout() {
		t.Fatal("wrong value for timeout")
	}
}
func TestCause(t *testing.T) {
	var (
		forever       = 1e6 * time.Second
		parentCause   = fmt.Errorf("parentCause")
		childCause    = fmt.Errorf("childCause")
		tooSlow       = fmt.Errorf("tooSlow")