Update ConnectivityManagerNetworkMonitor.kt

core/data/src/main/java/com/google/samples/apps/nowinandroid/core/data/util/ConnectivityManagerNetworkMonitor.kt

@@ -36,11 +36,13 @@ import javax.inject.Inject
 class ConnectivityManagerNetworkMonitor @Inject constructor(
     @ApplicationContext private val context: Context,
 ) : NetworkMonitor {
-    override val isOnline: Flow<Boolean> {
+    override val isOnline: Flow<Boolean> = callbackFlow {
         val connectivityManager = context.getSystemService<ConnectivityManager>()
-            ?: return flowOf(false)
-
-        return callbackFlow {
+        ?: run {
+            channel.trySend(false)
+            channel.close()
+            return@callbackFlow
+        }
 
         /**
          * The callback's methods are invoked on changes to *any* network, not just the active