Multiple Connectivity instances breaks onConnectivityChanged

[kibantony]

Using the connectivity plugin, if one creates multiple Connectivity() objects and listens to onConnectivityChanged, only one instance will receive events via the onConnectivityChanged stream.

Steps to Reproduce

1. Run this app on a real iOS or Android device: https://gist.github.com/kibantony/7208a3feb786f5e41ecdb9fc5581d345
2. With the app running, swipe up/down (depending on the platform) to bring up the OS shortcuts and turn off the network (Airplane mode).
3. Return to the app and notice that only one of the Connectivity Status lines was updated.

Logs

Notice in the logs that onConnectivityChanged is only called for Connectivity instance B.

I/flutter ( 5122): A checkConnectivity: ConnectivityResult.wifi
I/flutter ( 5122): B onConnectivityChanged: ConnectivityResult.wifi
I/flutter ( 5122): B checkConnectivity: ConnectivityResult.wifi
I/flutter ( 5122): B onConnectivityChanged: ConnectivityResult.wifi
I/flutter ( 5122): B onConnectivityChanged: ConnectivityResult.none

Flutter Doctor

[✓] Flutter (Channel beta, v0.7.3, on Mac OS X 10.13.6 17G65, locale en-US)
    • Flutter version 0.7.3 at /Users/tony/afero/flutter
    • Framework revision 3b309bda07 (2 weeks ago), 2018-08-28 12:39:24 -0700
    • Engine revision af42b6dc95
    • Dart version 2.1.0-dev.1.0.flutter-ccb16f7282

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
    • Android SDK at /Users/tony/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-27, build-tools 27.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
    • All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 9.4.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 9.4.1, Build version 9F2000
    • ios-deploy 1.9.2
    • CocoaPods version 1.5.3

[✓] Android Studio (version 3.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 27.1.1
    • Dart plugin version 173.4700
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[✓] VS Code (version 1.27.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 2.18.0

[✓] Connected devices (2 available)
    • SAMSUNG SM G925A • 02157df24a2a2e0a                     • android-arm64 • Android 6.0.1 (API 23)
    • iPhone 8         • EEF6AF6E-7CBB-464D-9115-131D04A6A5B6 • ios           • iOS 11.4 (simulator)

• No issues found!

[kibantony]

Apologies for the following ramble, but I feel compelled to give some background in case anyone sees my contrived example code above and considers this issue trivial. It can be quite tricky for developers to diagnose and cope with this issue. For example a developer might include a third-party plugin such as flutter_offline which internally uses connectivity and subscribes to onConnectivityChanged. Then the developer might attempt to use connectivity functionality directly in the app, to say do a deferred login when the network connection is restored. The developer will find this functionality inexplicably doesn't work.
The solution I've used as a work-around is to make sure to use only a single instance of the Connectivity class throughout the app, which may preclude the use of external packages or components that maintain another instance.

[cyanglaz]

The issue is resolved with flutter/plugins@06fd96e
Updating Connectivity version to 0.4.0+1 should automatically fix the overriding issue.
I will close the issue. If any related issue is found, please reopen the issue with details.