if got := string(ss.Suffix()); got != "abc" {
		t.Errorf("got = %q; want abc", got)
	}
	ss.Write([]byte("defghijklmno"))
	if got := string(ss.Suffix()); got != "fghijklmno" {
		t.Errorf("got = %q; want fghijklmno", got)
	}
	if got, want := ss.Size(), int64(len("abc")+len("defghijklmno")); got != want {
		t.Errorf("Size = %d; want %d", got, want)
	}
	buf := make([]byte, ss.Size())