31     std::array<uint8_t, 1024> buffer;  in write()  local
32     std::span<uint8_t> out(buffer.begin(), 3);  in write()
47         if (data.size() + 3 > buffer.size())  in write()
50                 "too large {} > {}", data.size() + 3, buffer.size()));  in write()
52         buffer[0] = (netfn | 1) << 2;  in write()
53         buffer[0] |= lun;  in write()
54         buffer[1] = cmd;  in write()
55         buffer[2] = cc;  in write()
56         memcpy(&buffer[3], data.data(), data.size());  in write()
57         out = std::span<uint8_t>(buffer.begin(), data.size() + 3);  in write()
62         buffer[0] |= 1 << 2;  in write()
63         buffer[2] = 0xff;  in write()
70     std::array<uint8_t, 1024> buffer;  in read()  local
71     auto in = stdplus::fd::read(kcs, buffer);  in read()