updateEmpty

        fn updateEmpty(self: *Accumulator, input: anytype, comptime unroll_count: usize) usize {
            var i: usize = 0;

            if (unroll_count > 0) {
                const unrolled_bytes = unroll_count * 16;
                while (i + unrolled_bytes <= input.len) : (i += unrolled_bytes) {
                    inline for (0..unroll_count) |j| {
                        self.processStripe(input[i + j * 16 ..][0..16]);
                    }
                }
            }

            while (i + 16 <= input.len) : (i += 16) {
                self.processStripe(input[i..][0..16]);
            }

            return i;
        }