if err != nil {
		t.Fatal(err)
	}
	if string(slurp) != "ok" {
		t.Fatalf("got %q; want ok", slurp)
	}

	waitCondition(t, 1*time.Millisecond, func(d time.Duration) bool {
		if n := cst.tr.IdleConnKeyCountForTesting(); n != 0 {
			if d > 0 {
				t.Logf("%v idle conns still present after %v", n, d)
			}
			return false
		}
		return true
	})
	if got := logout.String(); got != "" {