NullPointerException when called after app is paused

[jinyus]

This plugin fails when attempting to read the clipboard after switching to another app.

Here is the stacktrace:

E/MethodChannel#flutter_clipboard_manager( 8348): Failed to handle method call
E/MethodChannel#flutter_clipboard_manager( 8348): java.lang.NullPointerException: Attempt to invoke virtual method 'int android.content.ClipData.getItemCount()' on a null object reference
E/MethodChannel#flutter_clipboard_manager( 8348): 	at com.example.flutter_clipboard_manager.FlutterClipboardManagerPlugin.onMethodCall(FlutterClipboardManagerPlugin.java:49)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:233)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:85)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:692)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at android.os.MessageQueue.next(MessageQueue.java:336)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at android.os.Looper.loop(Looper.java:174)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at android.app.ActivityThread.main(ActivityThread.java:7356)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
E/MethodChannel#flutter_clipboard_manager( 8348): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
E/DartMessenger( 8348): Uncaught exception in binary message listener
E/DartMessenger( 8348): java.lang.IllegalStateException: Reply already submitted
E/DartMessenger( 8348): 	at io.flutter.embedding.engine.dart.DartMessenger$Reply.reply(DartMessenger.java:139)
E/DartMessenger( 8348): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:253)
E/DartMessenger( 8348): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:85)
E/DartMessenger( 8348): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:692)
E/DartMessenger( 8348): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/DartMessenger( 8348): 	at android.os.MessageQueue.next(MessageQueue.java:336)
E/DartMessenger( 8348): 	at android.os.Looper.loop(Looper.java:174)
E/DartMessenger( 8348): 	at android.app.ActivityThread.main(ActivityThread.java:7356)
E/DartMessenger( 8348): 	at java.lang.reflect.Method.invoke(Native Method)
E/DartMessenger( 8348): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
E/DartMessenger( 8348): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

Code to reproduce:

Timer.periodic(Duration(seconds:2), (_) async {
      final text = await FlutterClipboardManager.copyFromClipBoard();
      print('got clipboard data: $text');
    });

press go into recent screenpress home button on android so the app will be in the paused state.