const char *ptr = reinterpret_cast<char *>(
memmem(existing_data->data() + start_at, existing_data->size() - start_at,
"\r\n\r\n", 4));
const char *ptr = reinterpret_cast<char *>(
memmem(existing_data->data() + start_at, existing_data->size() - start_at,
"\r\n\r\n", 4));