t.Run("NegativeSize", func(t *testing.T) {
		tw := NewWriter(new(bytes.Buffer))
		hdr := &Header{Name: "small.txt", Size: -1}
		if err := tw.WriteHeader(hdr); err == nil {
			t.Fatalf("WriteHeader() = nil, want non-nil error")
		}
	})

	t.Run("BeforeHeader", func(t *testing.T) {
		tw := NewWriter(new(bytes.Buffer))
		if _, err := tw.Write([]byte("Kilts")); err != ErrWriteTooLong {

	}
	if _, err := tw.Write(data); err != nil {
		t.Fatalf("tw.Write: %v", err)
	}
	if err := tw.Close(); err != nil {
		t.Fatalf("tw.Close: %v", err)
	}

	// Read it back.
	tr := NewReader(&b)
	rHdr, err := tr.Next()
	if err != nil {
		t.Fatalf("tr.Next: %v", err)
	}
	if !reflect.DeepEqual(rHdr, hdr) {
		t.Errorf("Header mismatch.\n got %+v\nwant %+v", rHdr, hdr)
	}
	rData, err := io.ReadAll(tr)

	SLBIE R3                        // 7c001b64
	SLBMFEE R3, R4                  // 7c801f26
	SLBMFEV R3, R4                  // 7c801ea6
	SLBMTE R3, R4                   // 7c801b24

	TW $31, R0, R0                  // 7fe00008
	TD $31, R0, R0                  // 7fe00088
	DARN $1, R5                     // 7ca105e6

	DCBF (R3)(R4)                   // 7c0418ac
	DCBF (R3)(R0)                   // 7c0018ac