[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Bad state: Cannot add event after closing

[MoShenGuo]

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Bad state: Cannot add event after closing
#0 _StreamController.add (dart:async/stream_controller.dart:605:24)
#1 FlutterBlueElves._onToDart (package:flutter_blue_elves/flutter_blue_elves.dart:163:37)
#2 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#3 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:365:11)
#4 _DelayedData.perform (dart:async/stream_impl.dart:541:14)
#5 _PendingEvents.handleNext (dart:async/stream_impl.dart:646:11)
#6 _PendingEvents.schedule. (dart:async/stream_impl.dart:617:7)
#7 _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#8 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Bad state: Cannot add event after closing
#0 _StreamController.add (dart:async/stream_controller.dart:605:24)
#1 FlutterBlueElves._onToDart (package:flutter_blue_elves/flutter_blue_elves.dart:163:37)
#2 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#3 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:365:11)
#4 _DelayedData.perform (dart:async/stream_impl.dart:541:14)
#5 _PendingEvents.handleNext (dart:async/stream_impl.dart:646:11)
#6 _PendingEvents.schedule. (dart:async/stream_impl.dart:617:7)
#7 _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#8 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Bad state: Cannot add event after closing