flutter_barcode_scanner: CRASH java.lang.NullPointerException: Attempt to invoke interface method 'void

java.lang.NullPointerException: Attempt to invoke interface method 'void io.flutter.plugin.common.EventChannel$EventSink.success(java.lang.Object)' on a null object reference
E/AndroidRuntime(32669): 	at com.amolg.flutterbarcodescanner.FlutterBarcodeScannerPlugin$1.run(FlutterBarcodeScannerPlugin.java:201)
E/AndroidRuntime(32669): 	at android.os.Handler.handleCallback(Handler.java:883)
E/AndroidRuntime(32669): 	at android.os.Handler.dispatchMessage(Handler.java:100)
E/AndroidRuntime(32669): 	at android.os.Looper.loop(Looper.java:237)
E/AndroidRuntime(32669): 	at android.app.ActivityThread.main(ActivityThread.java:7857)
E/AndroidRuntime(32669): 	at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(32669): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
E/AndroidRuntime(32669): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1076)
I/Process (32669): Sending signal. PID: 32669 SIG: 9
Lost connection to device.

what i try to do is stream barcodes and get only qrcode not standart ean carcodes.

String res = await FlutterBarcodeScanner.getBarcodeStreamReceiver(
            "#ff6666", "Cancel", true, ScanMode.QR)
        .firstWhere((code) {
      print("singleWhere $code");
      if (code.toString().startsWith("http")) {
        print("founded");
        return true;
      }
      return false;
    });

using latest version 1.0