ServerInterceptorContext should provide closeFuture similar to ServerCallContext

[octo47]

Is your feature request related to a problem? Please describe it.

As for today ServerInterceptorContext does not have any way to handle abnormal stream termination (task cancelled, client resets connection in streaming calls).
In such an event interceptor will have no chance to be called as no .end() messages will be passed down ServerInterceptorPipeline.

Result of such behaviour may affect many use cases: tracing (lingering open spans), metrics (some calls will not be recorded), logging (errors will not be logged)

Describe the solution you'd like

Add closeFuture to ServerInterceptorContext (similar to ServerCallContext):

• var closeFuture: EventLoopFuture { get }

Describe alternatives you've considered

Proposed solution is in line how it currently works for ServerCallContext

Additional context

swift-interceptors.tar.gz

# server
swift run route-server
# client
swift run route-client

to make client die in bidir route chat

# run with kill-switch
swift run route-client --kill-process

so as a result normal run

2023-01-11T11:41:21+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] RECV metadata
2023-01-11T11:41:21+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] RECV message
....
2023-01-11T11:41:24+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] SEND message
2023-01-11T11:41:24+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] RECV end
2023-01-11T11:41:24+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat grpc.status=ok (0) [RouteGuideServer] SEND end

and with kill switch

2023-01-11T11:42:49+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] RECV metadata
2023-01-11T11:42:49+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] RECV message
...
2023-01-11T11:42:50+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] SEND message
2023-01-11T11:42:50+0000 debug route-server : grpc.path=/routeguide.RouteGuide/RouteChat [RouteGuideServer] SEND message

Note no SEND end messages (edited)