BillingClient wrapper with Coroutines and SharedFlow

Biller.kt

@Singleton
class Biller @Inject constructor(
    @ApplicationContext private val context: Context,
) : PurchasesUpdatedListener, BillingClientStateListener {
    
    private var billingClient: BillingClient =
        BillingClient.newBuilder(context)
            .setListener(this)
            .enablePendingPurchases()
            .build()
        
    private val billingClientStatus = MutableSharedFlow<Int>(
        replay = 1,
        onBufferOverflow = BufferOverflow.DROP_OLDEST
    )
    
    override fun onBillingSetupFinished(result: BillingResult) {
        billingClientStatus.tryEmit(result.responseCode)
    }

    override fun onBillingServiceDisconnected() {
        billingClientStatus.tryEmit(BillingClient.BillingResponseCode.SERVICE_DISCONNECTED)
    }
    
    // ...
    
    // Suspend until billingClientStatus == BillingClient.BillingResponseCode.OK
    private suspend fun requireBillingClientSetup(): Boolean =
        withTimeoutOrNull(TIMEOUT_MILLIS) {
            billingClientStatus.first { it == BillingClient.BillingResponseCode.OK }
            true
        } ?: false
   
    init {
        billingClientStatus.tryEmit(BillingClient.BillingResponseCode.SERVICE_DISCONNECTED)
        billingClientStatus.observe(ProcessLifecycleOwner.get()) {
            when (it) {
                BillingClient.BillingResponseCode.OK -> with (billingClient) {
                    updateSkuPrices()
                    handlePurchases()
                }
                else -> {
                    delay(RETRY_MILLIS)
                    billingClient.startConnection(this@Biller)
                }
            }
        }
    }

    private companion object {
        private const val TIMEOUT_MILLIS = 2000L
        private const val RETRY_MILLIS = 3000L
    }
}