update readme

packages/connectivity_plus/connectivity_plus/README.md

@@ -58,7 +58,9 @@ if (connectivityResult.contains(ConnectivityResult.mobile)) {
 ```
 
 You can also listen for active connectivity types changes by subscribing to the stream
-exposed by the plugin:
+exposed by the plugin.
+
+This method should ensure emitting only distinct values.
 
 ```dart
 import 'package:connectivity_plus/connectivity_plus.dart';
@@ -99,6 +101,8 @@ _`none` is supported on all platforms by default._
 
 Connectivity changes are no longer communicated to Android apps in the background starting with Android O (8.0). You should always check for connectivity status when your app is resumed. The broadcast is only useful when your application is in the foreground.
 
+To ensure connectivity changes on Android are tracked correctly, an event containing `[ConnectivityResult.none]` may be emitted in during connectivity changes. e.g. Going from WiFi to mobile network may emit: `[wifi] -> [none] -> [mobile]`.
+
 ### iOS & MacOS
 
 On iOS simulators, the connectivity types stream might not update when Wi-Fi status changes. This is a known issue.