Count(benchStr, "=")
		}
	}
	for _, size := range indexSizes {
		b.Run(fmt.Sprintf("%d", size), func(b *testing.B) {
			benchFunc(b, benchStr[:size])
		})
	}

}

var makeFieldsInput = func() string {
	x := make([]byte, 1<<20)
	// Input is ~10% space, ~10% 2-byte UTF-8, rest ASCII non-space.
	for i := range x {
		switch rand.Intn(10) {
		case 0:
			x[i] = ' '
		case 1:

			return ct.r == r
		}) != ct.expected {
			t.Errorf("ContainsFunc(%q, func(%q)) = %v, want %v",
				ct.b, ct.r, !ct.expected, ct.expected)
		}
	}
}

var makeFieldsInput = func() []byte {
	x := make([]byte, 1<<20)
	// Input is ~10% space, ~10% 2-byte UTF-8, rest ASCII non-space.
	for i := range x {
		switch rand.Intn(10) {
		case 0:
			x[i] = ' '
		case 1: