// previously returned strings.
	b.WriteString("bbb")
	check(t, &b, "bbb")
	if want := "aaa"; s != want {
		t.Errorf("previous String result changed after Reset: got %q; want %q", s, want)
	}
}

func TestBuilderGrow(t *testing.T) {
	for _, growLen := range []int{0, 100, 1000, 10000, 100000} {
		p := bytes.Repeat([]byte{'a'}, growLen)
		allocs := testing.AllocsPerRun(100, func() {
			var b Builder