setCharacteristicNotification example is wrong

[KaneZMY]

You must writeDescriptor after gatt.setCharacteristicNotification to inform peripheral, it's NOT specific to Heart Rate Measurement.

fun setCharacteristicNotification() {
    gatt?.let { gatt ->
        gatt.setCharacteristicNotification(characteristic, true)
        val CCC_DESCRIPTOR_UUID: UUID = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")
        val descriptor = characteristic?.getDescriptor(CCC_DESCRIPTOR_UUID)?.apply {
            value = BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE
        }
        gatt.writeDescriptor(descriptor)

https://developer.android.com/guide/topics/connectivity/bluetooth/transfer-ble-data is a bad document.
https://developer.android.com/guide/topics/connectivity/bluetooth-le#notification is good document.
Please update document and examples, save some time for others