static void attribute_read_cb(struct gatt_db_attribute *attrib, int err,
					const uint8_t *value, size_t length,
					void *user_data)
{
	struct iovec *iov = user_data;

	iov->iov_base = (void *) value;
	iov->iov_len = length;
}
static void attribute_read_cb(struct gatt_db_attribute *attrib, int err,
					const uint8_t *value, size_t length,
					void *user_data)
{
	struct iovec *iov = user_data;

	iov->iov_base = (void *) value;
	iov->iov_len = length;
}