Sending data after the client got closed crashed the program instead of sending an error.

Sending data after the client got closed crashed the program instead of sending an error upwards for the programmer to handle it.

<version of the grpc-dart packages used; see your pubspec.lock file> grpc: ^3.0.2

Repro steps

1. step1
2. step2
3. step3

Expected result: The error gets passed up and can be captured using handleError or try-catch

Actual result: The program crash without a way to capture the error

Details

<Include any other relevant details, logs, etc.>

Log:

Unhandled exception: Bad state: Cannot add event after closing #0 StreamController.add (dart:async/stream_controller.dart:595:24) #1 StreamSinkWrapper.add (dart:async/stream_controller.dart:867:13) #2 TransportStream.sendHeaders (package:http2/transport.dart:147:22) #3 ServerHandler.sendTrailers (package:grpc/src/server/handler.dart:361:13) #4 ServerHandler.sendError (package:grpc/src/server/handler.dart:410:5) #5 ServerHandler._onResponse (package:grpc/src/server/handler.dart:287:7) #6 _RootZone.runUnaryGuarded (dart:async/zone.dart:1618:10) #7 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11) #8 _DelayedData.perform (dart:async/stream_impl.dart:591:14) #9 _StreamImplEvents.handleNext (dart:async/stream_impl.dart:706:11) #10 _PendingEvents.schedule. (dart:async/stream_impl.dart:663:7) #11 _microtaskLoop (dart:async/schedule_microtask.dart:40:21) #12 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5) #13 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:122:13) #14 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:193:5)

Process finished with exit code 255

I saw that the there is a comment above the method sendHeaders line 146 in the file .pub-cache/hosted/pub.dartlang.org/http2-2.0.0/lib/transport.dart saying // For convenience only.

So I have removed the call for it in the method sendTrailers line 361 in the file .pub-cache/hosted/pub.dartlang.org/grpc-3.0.2/lib/src/server/handler.dart And the crashes stopped.