Quarkus Resteasy Reactive does not respect keep-alive when using Multi<>s

[rasmusfaber]

Describe the bug

Quarkus Resteasy Reactive kills connections even if Connection: keep-alive is specified and acknowledged by the server.

The problem only occurs when returning Multi<>s, not when returning Uni<>s or synchronous results.

A simple method such as

    @GET
    public Multi<String> async(){
        return Multi.createFrom().item("async");
    }

and then calling

curl http://localhost:8080 http://localhost:8080 -v -H "Connection: keep-alive

reproduces the problem.

Expected behavior

Quarkus Resteasy Reactive should behave like non-reactive and keep the connection alive.

Actual behavior

The connection is dead after the first request.

To Reproduce

Small project based on the Quarkus Reactive quick-start.

https://github.com/rasmusfaber/quarkus-resteasy-reactive-connection-drop

Steps to reproduce the behavior:

1. Run the included tests and notice that testHelloEndpointAsyncMulti fails.
   Or
2. Build and start the application
3. Run curl http://localhost:8081/hello/async http://localhost:8081/hello/async -v -H "Connection: keep-alive"
4. Notice that the second connection fails and curl needs to create a new connection (compare with curl http://localhost:8081/hello/sync http://localhost:8081/hello/sync -v -H "Connection: keep-alive")

Environment (please complete the following information):

Output of uname -a or ver

Linux xxx 5.4.0-73-generic #82~18.04.1-Ubuntu SMP Fri Apr 16 15:10:02 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Output of java -version

openjdk version "15.0.2" 2021-01-19
OpenJDK Runtime Environment AdoptOpenJDK (build 15.0.2+7)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 15.0.2+7, mixed mode, sharing)

Quarkus version or git rev

2.0.0.Final (also 1.13.3.Final)

Build tool (ie. output of mvnw --version or gradlew --version)

apache-maven-3.6.3

[quarkus-bot]

/cc @FroMage, @geoand, @stuartwdouglas

[rasmusfaber]

I guess it is because of this line:

quarkus/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/handlers/PublisherResponseHandler.java

Line 141 in 2cbd177

requestContext.serverRequest().closeConnection();

The connection isn't closed when returning an Uni<>.