@Produces(MediaTypeNames.EVENT_STREAM)
        @Streaming(true)
        @Get("/serverSentEventPublisher")
        @ResponseConverter(ServerSentEventResponseConverterFunction.class)
        public Publisher<ServerSentEvent> serverSentEventPublisher() {
            return StreamMessage.of(ServerSentEvent.ofData("serverSentEventPublisher"));
        }
A mock service for testing {@link ServerSentEventResponseConverterFunction}.
core/src/test/java/com/linecorp/armeria/internal/server/annotation/ResponseStreamingTest.java