How can I identify the transmission completion of a packet when using NCS?

Hi Nordic team,

I'm using the bt_gatt_notify_cb function to send notifications about data.

In the SDK, I can ascertain that the data has been successfully sent through the "BLE_GATTS_EVT_HVN_TX_COMPLETE" event. However, in NCS, which event or function can provide me with this information?

I want to find out how many packets are waiting in the queue.

Thank you.