Server -> Client channel not closed when client is terminated

[paul-lysak]

Condition: Some objects are being streamed from the server to the client through the channel
and the client is somehow terminated.

Actual behavior: The channel remains open on the server. If it's unbounded - server may keep writing there until memory ends,
if it's Rendez-Vous channel - it soon gets blocked forever.

Expected behavior: the channel is closed, an exception is thrown if the server tries to write something there.

How to reproduce: take the example code from https://github.com/rouzwawi/grpc-kotlin/tree/master/grpc-kotlin-example-chatserver,
replace the code under the try clause in chat method in ChatService.kt with this to cross out client -> server channel (which is being closed correctly when client shuts down):

                //removed for test
//                for (chatMessage in requests) {
                //added for test
                for (i in 0..100) {
                    //added for test
                    val chatMessage = ChatMessage.newBuilder().setMessage("msg $i").setFrom("TEST").build()
                    println("Got request from $requests:")
                    println(chatMessage)
                    val message = createMessage(chatMessage)
                    clientChannels
                            .filter { it.name != chatMessage.from }
                            .forEach { other ->
                                println("Sending to $other")
                                other.channel.send(message)
                            }
                    //added for test
                    delay(1000)
                }

Build the project and run the server as described in https://github.com/rouzwawi/grpc-kotlin/blob/master/grpc-kotlin-example-chatserver/README.md.
In another terminal run the client as described in the same doc, enter the username. For a while see the test messages being generated - there are logs both in client and server logs.
Terminate the client - see that the server keeps printing "Sending to Client ...".