{
			name: "fill error, discard less",
			r: newScriptedReader(func(p []byte) (n int, err error) {
				if len(p) < 5 {
					panic("unexpected small read")
				}
				return 5, errors.New("5-then-error")
			}),
			n:            4,
			want:         4,
			wantErr:      nil,
			wantBuffered: 1,
		},
		{
			name: "fill error, discard equal",

	// which names a file in the testdata/ directory containing the
	// uncompressed expected content.
	// If content is very large, an alternative to setting Content or File
	// is to set Size, which will then be checked against the header-reported size
	// but will bypass the decompressing of the actual data.
	// This last option is used for testing very large (multi-GB) compressed files.
	ContentErr error
	Content    []byte
	File       string

// Single quotes and double quotes are recognized to prevent splitting within the
// quoted region, and are removed from the resulting substrings. If a quote in s
// isn't closed err will be set and r will have the unclosed argument as the
// last element. The backslash is used for escaping.
//
// For example, the following string:
//
//	`a b:"c d" 'e''f'  "g\""`
//
// Would be parsed as:
//

	FMOVQ.P	11(R10), F13                                    // 4db5c03c
	FMOVQ.W	11(R20), F15                                    // 8fbec03c

// storing $0 to memory, $0 will be replaced with ZR.
	MOVD	$0, (R1)  // 3f0000f9
	MOVW	$0, (R1)  // 3f0000b9
	MOVWU	$0, (R1)  // 3f0000b9
	MOVH	$0, (R1)  // 3f000079
	MOVHU	$0, (R1)  // 3f000079
	MOVB	$0, (R1)  // 3f000039

	windows := []int{1, 2, 3, 4, 15, 16, 17, 31, 32, 33, 63, 64, 65, 128}
	for i := 0; i <= len(b); i++ {
		for _, window := range windows {
			if window > len(b[i:]) {
				window = len(b[i:])
			}
			// Fill the window with non-match
			for j := 0; j < window; j++ {
				b[i+j] = byte(100)
			}
			// Try to find something that doesn't exist
			p := Count(b[i:i+window], []byte{0})
			if p != 0 {