Creating a callbackFlow for BluetoothLeAdvertiser

Question

I'm trying to make a data source and repository for a Bluetooth Low Energy GATT server. The app needs to display whether the app is currently advertising.

The docs suggest that I would use a callbackFlow for this, because BluetoothLeAdvertiser uses callbacks to report when advertising has successfuly begun.

However, callbackFlow still seems to require you to define the callback within the flow scope, but advertising operations can only have one callback attached, which must be passed in to BluetoothLeAdvertiser.startAdvertising. Advertising may be started and stopped at any time by the user.

This is an issue because the advertising callback cannot be defined in the flow scope, as this would require the advertising to start when the flow is created, and end when the flow is closed.

My solution was to create an list of callbacks, and add callbacks created in the flow to this list. When advertising is started/stopped, I call all of these callbacks.

Is this the best practice for this type of situation, or is there a better solution?

import android.annotation.SuppressLint
import android.bluetooth.BluetoothManager
import android.bluetooth.le.AdvertiseCallback
import android.content.Context
import kotlinx.coroutines.channels.awaitClose
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.callbackFlow

@SuppressLint("MissingPermission")
class BleDataSource(private val bluetoothManager: BluetoothManager, private val context: Context) {
  private val advertiseFlowCallbacks: MutableList<(isAdvertising: Boolean) -> Unit> = mutableListOf()
  private val advertiseCallback = object : AdvertiseCallback() {
    override fun onStartSuccess(settingsInEffect: AdvertiseSettings) {
      super.onStartSuccess(settingsInEffect)
      advertiseFlowCallbacks.forEach { it(true) }
    }
  }
  
  fun getAdvertisingState(): Flow<Boolean> = callbackFlow {
    val callback: (isAdvertising: Boolean) -> Unit = {
      trySend(it)
    }

    advertiseFlowCallbacks.add(callback)
    awaitClose { advertiseFlowCallbacks.remove(callback) }
  }

  fun startAdvertising() {
    // The definitions of adSettings, adData, and scanResponseData are not relevant
    bluetoothManager.adapter.bluetoothLeAdvertiser.startAdvertising(adSettings, adData, scanResponseData, advertiseCallback)
  }


  fun stopAdvertising() {
    bluetoothManager.adapter.bluetoothLeAdvertiser.stopAdvertising(advertiseCallback)
    advertiseFlowCallbacks.forEach { it(false) }
  }
}