ble_gatt_reliable_attr_fn
The host will free the attribute mbufs automatically after the callback is executed. The application can take ownership of the mbufs and prevent them from being freed by assigning NULL to each attribute's om field.
Syntax
typedef int ble_gatt_reliable_attr_fn(uint16_t conn_handle,
const struct ble_gatt_error *error,
struct ble_gatt_attr *attrs,
uint8_t num_attrs, void *arg);