}

func BenchmarkEqualBothUnaligned(b *testing.B) {
	sizes := []int{64, 4 << 10}
	if !isRaceBuilder {
		sizes = append(sizes, []int{4 << 20, 64 << 20}...)
	}
	maxSize := 2 * (sizes[len(sizes)-1] + 8)
	if len(bmbuf) < maxSize {
		bmbuf = make([]byte, maxSize)
	}

	for _, n := range sizes {
		for _, off := range []int{0, 1, 4, 7} {
			buf1 := bmbuf[off : off+n]
			buf2Start := (len(bmbuf) / 2) + off

		if ok1 || ok2 {
			return ok1 && ok2
		}
		return x == y
	}
	for _, v := range vectors {
		t.Run(path.Base(v.file), func(t *testing.T) {
			const maxSize = 10 << 10 // 10KiB
			buf := new(bytes.Buffer)
			tw := NewWriter(iotest.TruncateWriter(buf, maxSize))

			for i, tf := range v.tests {
				switch tf := tf.(type) {
				case testHeader:
					err := tw.WriteHeader(&tf.hdr)
					if !equalError(err, tf.wantErr) {